Treatment of pain by subarachnoid administration of sustained-release liposomal anesthetic compositions

ABSTRACT

In some embodiments provided herein is a method of treating pain, the method comprising injecting into the subarachnoid space of the subject a pharmaceutical composition comprising: a) a multivesicular liposome comprising: at least one amphipathic lipid, and at least one neutral lipid; and b) an aqueous phase comprising bupivacaine phosphate, wherein the aqueous phase is encapsulated within the multivesicular liposome.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application Ser.No. 62/959,550, filed Jan. 10, 2020, U.S. Provisional Application Ser.No. 63/064,760, filed Aug. 12, 2020, and U.S. Provisional ApplicationSer. No. 63/066,477, filed Aug. 17, 2020, each of which is incorporatedby reference herein in its entirety.

BACKGROUND

Extended-release anesthetic formulations of bupivacaine have beendeveloped to prolong the duration of analgesia. Multivesicular liposomalbupivacaine has been approved for single-dose infiltration to producepostsurgical local analgesia and as an interscalene brachial plexusnerve block to produce postsurgical regional analgesia (see EXPAREL®prescribing information,https://www.accessdata.fda.gov/drugsatfda_docs/label/2018/022496s91b1.pdf). It would also be desirable, however, to provide treatmentfor pain in a region below the diaphragm that is both safe andeffective. Zel et al., British Journal of Anaesthesia, 122(3): 1e9(2018), accepted Oct. 19, 2019, doi: 10.1016/j.bja.2018.10.025, havedescribed subarachnoid administration in pigs, but cautioned that itremains necessary to evaluate the pharmacodynamic properties ofliposomal bupivacaine and dose-response before regulatory approval forsubarachnoid administration in humans, either in clinical research orpractice. Similarly, Joshi et al., who administered liposomalbupivacaine by intrathecal (subarachnoid) injection into dogs, notedthat clinical observations from animal studies should be interpretedwith appropriate caution. See Journal of Pain Research 2015:8 781-789.

Accordingly, there continues to be a need for methods of treating painin a subject, such as pain in a region below the diaphragm in a subject,such as a human subject.

SUMMARY

In some embodiments provided herein is a method of treating pain in asubject, the method comprising injecting into the subarachnoid space ofthe subject a pharmaceutical composition comprising: a) a multivesicularliposome comprising: at least one amphipathic lipid, and at least oneneutral lipid; and b) an aqueous phase comprising: at least onepolyhydroxy carboxylic acid and at least one di- or tri-protic mineralacid; and bupivacaine phosphate, wherein the aqueous phase isencapsulated within the multivesicular liposome.

In some embodiments provided herein is a method of treating pain in asubject, the method comprising injecting into the subarachnoid space ofthe subject a pharmaceutical composition comprising: a) a multivesicularliposome comprising: at least one amphipathic lipid, and at least oneneutral lipid; and b) an aqueous phase comprising bupivacaine phosphate,wherein the aqueous phase is encapsulated within the multivesicularliposome.

In some embodiments provided herein is a method of treating pain in asubject, the method comprising injecting into the subarachnoid space ofthe subject a pharmaceutical composition comprising multivesicularliposomes encapsulating bupivacaine phosphate, said multivesicularliposomes comprising:

bupivacaine or a salt thereof;

phosphoric acid;

a lipid component comprising at least one amphipathic lipid and at leastone neutral lipid lacking a hydrophilic head group; and,

optionally, a cholesterol and/or a plant sterol wherein saidmultivesicular liposomes are made by a process comprising:

a) preparing a first aqueous component comprising phosphoric acid;

b) preparing a lipid component comprising at least one organic solvent,at least one amphipathic lipid, and at least one neutral lipid lacking ahydrophilic head group;

c) mixing said first aqueous component and said lipid component to forma water-in-oil emulsion, wherein at least one component comprisesbupivacaine or a salt thereof;

d) mixing said water-in-oil emulsion with a second aqueous component toform solvent spherules; and

e) removing the organic solvent from the solvent spherules to formmultivesicular liposomes encapsulating bupivacaine phosphate.

In some embodiments provided herein is a method of treating pain in asubject, the method comprising injecting into the subarachnoid space ofthe subject a multivesicular liposomal particle pharmaceuticalcomposition made by a process comprising: a) providing a volume of firstemulsion by mixing a volume of a first aqueous phase and a volume of avolatile water-immiscible solvent phase, said solvent phase comprisingat least one amphipathic lipid and at least one neutral lipid; b) mixingand emulsifying said first emulsion and a volume of a second aqueousphase in a high shear mixer to provide a volume of a second emulsion,said second emulsion comprising a continuous aqueous phase; and c)removing the volatile water-immiscible solvent from the second emulsionto form a volume of multivesicular liposomal particle composition,wherein said solvent removal comprises contacting the second emulsionwith an inert gas flow; and wherein said process further comprisesprimary filtration of the multivesicular liposomal particle compositionby cross-flow filtration using a filter having a membrane where themultivesicular liposomal particle composition does not pass through themembrane; wherein all steps are carried out under aseptic conditions,and wherein all solutions are sterile filtered, and wherein themultivesicular liposomal particle composition is immediately suitablefor administration into humans; and wherein the primary filtrationcomprises: a first concentration of the multivesicular liposomalparticle composition; and a buffer exchange, resulting in a pH of themultivesicular liposomal particle composition of between about 5 andabout 8, and the primary filtration is conducted at a transmembranepressure of from about 0.1 psi to about 20 psi, such as to about 7 psi.

In some embodiments provided herein is a method of treating pain in asubject, the method comprising injecting into the subarachnoid space ofthe subject a multivesicular liposomal particle pharmaceuticalcomposition of pre-determined, uniform size distribution, made by aprocess comprising: a) providing a first emulsion by mixing a firstaqueous phase and a volatile water-immiscible solvent phase, saidsolvent phase comprising at least one amphipathic lipid and at least oneneutral lipid; b) mixing and emulsifying said first emulsion and asecond aqueous phase in a mixer to provide a second emulsion, saidsecond emulsion comprising a continuous aqueous phase; c) sparging thevolatile water-immiscible solvent from the second emulsion to form anaqueous suspension of multivesicular liposomal particles by bubbling aninert gas through the second emulsion using at least one sparge ring, atleast one sparge tube or at least one fit; d) primary filtration of theaqueous suspension of multivesicular liposomal particles by cross-flowfiltration using a filter to exchange the second aqueous phase with anaqueous component to provide an initial volume of aqueous media, whereinthe filter has a membrane pore size from 0.07 to 0.45 μm; e) secondaryfiltration by cross-flow filtration to reduce the initial volume toprovide a subsequent volume of aqueous media that is 10% to 90% of theinitial volume, further wherein the cross-flow filtration is carried outwith a process-scale tangential flow filter with a filtration area of 23square feet or more, wherein all steps are carried out under asepticconditions, f) the composition is prepared in quantities or batchesgreater than a liter; wherein the first emulsion is mixed in a firstemulsification vessel of at least 10 liters in volume; and g) whereinthe uniform size distribution has a number weighted mean particle sizeof at least 10 microns.

In some embodiments provided herein is a method of treating pain in asubject, the method comprising injecting into the subarachnoid space ofthe subject a composition comprising multivesicular liposomes comprisingbupivacaine or a salt thereof and having a structure including multiplenon-concentric chambers and comprising at least one amphipathic lipidand at least one neutral lipid, wherein said multivesicular liposomesare made by a process comprising removing organic solvent frommultivesicular liposomes pre-droplets that comprise a first componentcore and an aqueous phase shell with an evaporation apparatus, theevaporation apparatus comprising: a solvent removal vessel having a top,a bottom and a circular wall; at least one atomizing nozzle; a carriergas entrance orifice; a solvent removal gas exit orifice centrallyconnected to the top; and a product exit orifice connected to the bottomof the vessel,

wherein the process comprises: introducing the pre-droplets to thesolvent removal vessel; applying a carrier gas in a tangential directionto the circular wall through the carrier gas entrance orifice; andremoving a solvent removal gas through the solvent removal gas exitorifice to provide the large diameter synthetic membrane vesicles.

In some embodiments provided herein is a method of inducing motor blockin a subject, the method comprising injecting into the subarachnoidspace of the subject a pharmaceutical composition comprising: a) amultivesicular liposome comprising: at least one amphipathic lipid, andat least one neutral lipid; and b) an aqueous phase comprising: at leastone polyhydroxy carboxylic acid and at least one di- or tri-proticmineral acid; and bupivacaine phosphate, wherein the aqueous phase isencapsulated within the multivesicular liposome.

In some embodiments provided herein is a method of inducing motor blockin a subject, the method comprising injecting into the subarachnoidspace of the subject a pharmaceutical composition comprising: a) amultivesicular liposome comprising: at least one amphipathic lipid, andat least one neutral lipid; and b) an aqueous phase comprisingbupivacaine phosphate, wherein the aqueous phase is encapsulated withinthe multivesicular liposome.

In some embodiments provided herein is a method of inducing motor blockin a subject, the method comprising injecting into the subarachnoidspace of the subject a pharmaceutical composition comprisingmultivesicular liposomes encapsulating bupivacaine phosphate, saidmultivesicular liposomes comprising:

bupivacaine or a salt thereof;

phosphoric acid;

a lipid component comprising at least one amphipathic lipid and at leastone neutral lipid lacking a hydrophilic head group; and,

optionally, a cholesterol and/or a plant sterol wherein saidmultivesicular liposomes are made by a process comprising:

a) preparing a first aqueous component comprising phosphoric acid;

b) preparing a lipid component comprising at least one organic solvent,at least one amphipathic lipid, and at least one neutral lipid lacking ahydrophilic head group;

c) mixing said first aqueous component and said lipid component to forma water-in-oil emulsion, wherein at least one component comprisesbupivacaine or a salt thereof;

d) mixing said water-in-oil emulsion with a second aqueous component toform solvent spherules; and

e) removing the organic solvent from the solvent spherules to formmultivesicular liposomes encapsulating bupivacaine phosphate.

In some embodiments provided herein is a method of inducing motor blockin a subject, the method comprising injecting into the subarachnoidspace of the subject a multivesicular liposomal particle pharmaceuticalcomposition made by a process comprising: a) providing a volume of firstemulsion by mixing a volume of a first aqueous phase and a volume of avolatile water-immiscible solvent phase, said solvent phase comprisingat least one amphipathic lipid and at least one neutral lipid; b) mixingand emulsifying said first emulsion and a volume of a second aqueousphase in a high shear mixer to provide a volume of a second emulsion,said second emulsion comprising a continuous aqueous phase; and c)removing the volatile water-immiscible solvent from the second emulsionto form a volume of multivesicular liposomal particle composition,wherein said solvent removal comprises contacting the second emulsionwith an inert gas flow; and wherein said process further comprisesprimary filtration of the multivesicular liposomal particle compositionby cross-flow filtration using a filter having a membrane where themultivesicular liposomal particle composition does not pass through themembrane; wherein all steps are carried out under aseptic conditions,and wherein all solutions are sterile filtered, and wherein themultivesicular liposomal particle composition is immediately suitablefor administration into humans; and wherein the primary filtrationcomprises: a first concentration of the multivesicular liposomalparticle composition; and a buffer exchange, resulting in a pH of themultivesicular liposomal particle composition of between about 5 andabout 8, and the primary filtration is conducted at a transmembranepressure of from about 0.1 psi to about 20 psi, such as to about 7 psi.

In some embodiments provided herein is a method of inducing motor blockin a subject, the method comprising injecting into the subarachnoidspace of the subject a multivesicular liposomal particle pharmaceuticalcomposition of pre-determined, uniform size distribution, made by aprocess comprising: a) providing a first emulsion by mixing a firstaqueous phase and a volatile water-immiscible solvent phase, saidsolvent phase comprising at least one amphipathic lipid and at least oneneutral lipid; b) mixing and emulsifying said first emulsion and asecond aqueous phase in a mixer to provide a second emulsion, saidsecond emulsion comprising a continuous aqueous phase; c) sparging thevolatile water-immiscible solvent from the second emulsion to form anaqueous suspension of multivesicular liposomal particles by bubbling aninert gas through the second emulsion using at least one sparge ring, atleast one sparge tube or at least one fit; d) primary filtration of theaqueous suspension of multivesicular liposomal particles by cross-flowfiltration using a filter to exchange the second aqueous phase with anaqueous component to provide an initial volume of aqueous media, whereinthe filter has a membrane pore size from 0.07 to 0.45 μm; e) secondaryfiltration by cross-flow filtration to reduce the initial volume toprovide a subsequent volume of aqueous media that is 10% to 90% of theinitial volume, further wherein the cross-flow filtration is carried outwith a process-scale tangential flow filter with a filtration area of 23square feet or more, wherein all steps are carried out under asepticconditions, f) the composition is prepared in quantities or batchesgreater than a liter; wherein the first emulsion is mixed in a firstemulsification vessel of at least 10 liters in volume; and g) whereinthe uniform size distribution has a number weighted mean particle sizeof at least 10 microns.

In some embodiments provided herein is a method of inducing motor blockin a subject, the method comprising injecting into the subarachnoidspace of the subject a composition comprising multivesicular liposomescomprising bupivacaine or a salt thereof and having a structureincluding multiple non-concentric chambers and comprising at least oneamphipathic lipid and at least one neutral lipid, wherein saidmultivesicular liposomes are made by a process comprising removingorganic solvent from multivesicular liposomes pre-droplets that comprisea first component core and an aqueous phase shell with an evaporationapparatus, the evaporation apparatus comprising: a solvent removalvessel having a top, a bottom and a circular wall; at least oneatomizing nozzle; a carrier gas entrance orifice; a solvent removal gasexit orifice centrally connected to the top; and a product exit orificeconnected to the bottom of the vessel,

wherein the process comprises: introducing the pre-droplets to thesolvent removal vessel; applying a carrier gas in a tangential directionto the circular wall through the carrier gas entrance orifice; andremoving a solvent removal gas through the solvent removal gas exitorifice to provide the large diameter synthetic membrane vesicles.

In some embodiments provided herein is a method of inducing sensoryblock in a subject, the method comprising injecting into thesubarachnoid space of the subject a pharmaceutical compositioncomprising: a) a multivesicular liposome comprising: at least oneamphipathic lipid, and at least one neutral lipid; and b) an aqueousphase comprising: at least one polyhydroxy carboxylic acid and at leastone di- or tri-protic mineral acid; and bupivacaine phosphate, whereinthe aqueous phase is encapsulated within the multivesicular liposome.

In some embodiments provided herein is a method of inducing sensoryblock in a subject, the method comprising injecting into thesubarachnoid space of the subject a pharmaceutical compositioncomprising: a) a multivesicular liposome comprising: at least oneamphipathic lipid, and at least one neutral lipid; and b) an aqueousphase comprising bupivacaine phosphate, wherein the aqueous phase isencapsulated within the multivesicular liposome.

In some embodiments provided herein is a method of inducing sensoryblock in a subject, the method comprising injecting into thesubarachnoid space of the subject a pharmaceutical compositioncomprising multivesicular liposomes encapsulating bupivacaine phosphate,said multivesicular liposomes comprising:

bupivacaine or a salt thereof;

phosphoric acid;

a lipid component comprising at least one amphipathic lipid and at leastone neutral lipid lacking a hydrophilic head group; and,

optionally, a cholesterol and/or a plant sterol wherein saidmultivesicular liposomes are made by a process comprising:

a) preparing a first aqueous component comprising phosphoric acid;

b) preparing a lipid component comprising at least one organic solvent,at least one amphipathic lipid, and at least one neutral lipid lacking ahydrophilic head group;

c) mixing said first aqueous component and said lipid component to forma water-in-oil emulsion, wherein at least one component comprisesbupivacaine or a salt thereof;

d) mixing said water-in-oil emulsion with a second aqueous component toform solvent spherules; and

e) removing the organic solvent from the solvent spherules to formmultivesicular liposomes encapsulating bupivacaine phosphate.

In some embodiments provided herein is a method of inducing sensoryblock in a subject, the method comprising injecting into thesubarachnoid space of the subject a multivesicular liposomal particlepharmaceutical composition made by a process comprising: a) providing avolume of first emulsion by mixing a volume of a first aqueous phase anda volume of a volatile water-immiscible solvent phase, said solventphase comprising at least one amphipathic lipid and at least one neutrallipid; b) mixing and emulsifying said first emulsion and a volume of asecond aqueous phase in a high shear mixer to provide a volume of asecond emulsion, said second emulsion comprising a continuous aqueousphase; and c) removing the volatile water-immiscible solvent from thesecond emulsion to form a volume of multivesicular liposomal particlecomposition, wherein said solvent removal comprises contacting thesecond emulsion with an inert gas flow; and wherein said process furthercomprises primary filtration of the multivesicular liposomal particlecomposition by cross-flow filtration using a filter having a membranewhere the multivesicular liposomal particle composition does not passthrough the membrane; wherein all steps are carried out under asepticconditions, and wherein all solutions are sterile filtered, and whereinthe multivesicular liposomal particle composition is immediatelysuitable for administration into humans; and wherein the primaryfiltration comprises: a first concentration of the multivesicularliposomal particle composition; and a buffer exchange, resulting in a pHof the multivesicular liposomal particle composition of between about 5and about 8, and the primary filtration is conducted at a transmembranepressure of from about 0.1 psi to about 20 psi, such as to about 7 psi.

In some embodiments provided herein is a method of inducing sensoryblock in a subject, the method comprising injecting into thesubarachnoid space of the subject a multivesicular liposomal particlepharmaceutical composition of pre-determined, uniform size distribution,made by a process comprising: a) providing a first emulsion by mixing afirst aqueous phase and a volatile water-immiscible solvent phase, saidsolvent phase comprising at least one amphipathic lipid and at least oneneutral lipid; b) mixing and emulsifying said first emulsion and asecond aqueous phase in a mixer to provide a second emulsion, saidsecond emulsion comprising a continuous aqueous phase; c) sparging thevolatile water-immiscible solvent from the second emulsion to form anaqueous suspension of multivesicular liposomal particles by bubbling aninert gas through the second emulsion using at least one sparge ring, atleast one sparge tube or at least one fit; d) primary filtration of theaqueous suspension of multivesicular liposomal particles by cross-flowfiltration using a filter to exchange the second aqueous phase with anaqueous component to provide an initial volume of aqueous media, whereinthe filter has a membrane pore size from 0.07 to 0.45 μm; e) secondaryfiltration by cross-flow filtration to reduce the initial volume toprovide a subsequent volume of aqueous media that is 10% to 90% of theinitial volume, further wherein the cross-flow filtration is carried outwith a process-scale tangential flow filter with a filtration area of 23square feet or more, wherein all steps are carried out under asepticconditions, f) the composition is prepared in quantities or batchesgreater than a liter; wherein the first emulsion is mixed in a firstemulsification vessel of at least 10 liters in volume; and g) whereinthe uniform size distribution has a number weighted mean particle sizeof at least 10 microns.

In some embodiments provided herein is a method of inducing sensoryblock in a subject, the method comprising injecting into thesubarachnoid space of the subject a composition comprisingmultivesicular liposomes comprising bupivacaine or a salt thereof andhaving a structure including multiple non-concentric chambers andcomprising at least one amphipathic lipid and at least one neutrallipid, wherein said multivesicular liposomes are made by a processcomprising removing organic solvent from multivesicular liposomespre-droplets that comprise a first component core and an aqueous phaseshell with an evaporation apparatus, the evaporation apparatuscomprising: a solvent removal vessel having a top, a bottom and acircular wall; at least one atomizing nozzle; a carrier gas entranceorifice; a solvent removal gas exit orifice centrally connected to thetop; and a product exit orifice connected to the bottom of the vessel,

wherein the process comprises: introducing the pre-droplets to thesolvent removal vessel; applying a carrier gas in a tangential directionto the circular wall through the carrier gas entrance orifice; andremoving a solvent removal gas through the solvent removal gas exitorifice to provide the large diameter synthetic membrane vesicles.

In some embodiments, the method of treating pain in a subject comprisesadministering an opioid to the subject following the injection of thepharmaceutical composition into the subarachnoid space of the subject.

In some embodiments, the opioid is administered in a total amount lessthan 50 mg in the first about 72 hours following the injection of thepharmaceutical composition into the subarachnoid space of the subject.

In some embodiments of the method of treating pain in a subject, whereinthe subject is a first subject, in the first about 72 hours followinginjection of the pharmaceutical composition into the subarachnoid spaceof the first subject the opioid is administered to the first subject ina total amount that is lower than the total amount of an opioid that isadministered to a second subject in the first about 72 hours followinginjection into the subarachnoid space of the second subject ofnon-liposomal bupivacaine containing the same amount of bupivacaine asthe pharmaceutical composition, wherein a pharmaceutical compositioncomprising: a) a multivesicular liposome comprising: at least oneamphipathic lipid, and at least one neutral lipid; and b) an aqueousphase comprising: at least one polyhydroxy carboxylic acid and at leastone di- or tri-protic mineral acid; and bupivacaine phosphate, whereinthe aqueous phase is encapsulated within the multivesicular liposome, isnot administered to the second subject.

In some embodiments of the method of treating pain in a subject, whereinthe subject is a first subject, in the first about 72 hours followinginjection of the pharmaceutical composition into the subarachnoid spaceof the first subject the opioid is administered to the first subject ina total amount that is lower than the total amount of an opioid that isadministered to a second subject in the first about 72 hours followinginjection into the subarachnoid space of the second subject ofnon-liposomal bupivacaine containing the same amount of bupivacaine asthe pharmaceutical composition, wherein a pharmaceutical compositioncomprising: a) a multivesicular liposome comprising: at least oneamphipathic lipid, and at least one neutral lipid; and b) an aqueousphase comprising bupivacaine phosphate, wherein the aqueous phase isencapsulated within the multivesicular liposome,

is not administered to the second subject.

In some embodiments of the method of treating pain in a subject, whereinthe subject is a first subject, in the first about 72 hours followinginjection of the pharmaceutical composition into the subarachnoid spaceof the first subject the opioid is administered to the first subject ina total amount that is lower than the total amount of an opioid that isadministered to a second subject in the first about 72 hours followinginjection into the subarachnoid space of the second subject ofnon-liposomal bupivacaine containing the same amount of bupivacaine asthe pharmaceutical composition, wherein a pharmaceutical compositioncomprising multivesicular liposomes encapsulating bupivacaine phosphate,said multivesicular liposomes comprising:

bupivacaine or a salt thereof;

phosphoric acid;

a lipid component comprising at least one amphipathic lipid and at leastone neutral lipid lacking a hydrophilic head group; and,

optionally, a cholesterol and/or a plant sterol wherein saidmultivesicular liposomes are made by a process comprising:

a) preparing a first aqueous component comprising phosphoric acid;

b) preparing a lipid component comprising at least one organic solvent,at least one amphipathic lipid, and at least one neutral lipid lacking ahydrophilic head group;

c) mixing said first aqueous component and said lipid component to forma water-in-oil emulsion, wherein at least one component comprisesbupivacaine or a salt thereof;

d) mixing said water-in-oil emulsion with a second aqueous component toform solvent e) removing the organic solvent from the solvent spherulesto form multivesicular liposomes encapsulating bupivacaine phosphate, isnot administered to the second subject.

In some embodiments of the method of treating pain in a subject, whereinthe subject is a first subject, in the first about 72 hours followinginjection of the pharmaceutical composition into the subarachnoid spaceof the first subject the opioid is administered to the first subject ina total amount that is lower than the total amount of an opioid that isadministered to a second subject in the first about 72 hours followinginjection into the subarachnoid space of the second subject ofnon-liposomal bupivacaine containing the same amount of bupivacaine asthe pharmaceutical composition, wherein a multivesicular liposomalparticle pharmaceutical composition made by a process comprising: a)providing a volume of first emulsion by mixing a volume of a firstaqueous phase and a volume of a volatile water-immiscible solvent phase,said solvent phase comprising at least one amphipathic lipid and atleast one neutral lipid; b) mixing and emulsifying said first emulsionand a volume of a second aqueous phase in a high shear mixer to providea volume of a second emulsion, said second emulsion comprising acontinuous aqueous phase; and c) removing the volatile water-immisciblesolvent from the second emulsion to form a volume of multivesicularliposomal particle composition, wherein said solvent removal comprisescontacting the second emulsion with an inert gas flow; and wherein saidprocess further comprises primary filtration of the multivesicularliposomal particle composition by cross-flow filtration using a filterhaving a membrane where the multivesicular liposomal particlecomposition does not pass through the membrane; wherein all steps arecarried out under aseptic conditions, and wherein all solutions aresterile filtered, and wherein the multivesicular liposomal particlecomposition is immediately suitable for administration into humans; andwherein the primary filtration comprises: a first concentration of themultivesicular liposomal particle composition; and a buffer exchange,resulting in a pH of the multivesicular liposomal particle compositionof between about 5 and about 8, and the primary filtration is conductedat a transmembrane pressure of from about 0.1 psi to about 20 psi, suchas to about 7 psi,

is not administered to the second subject.

In some embodiments of the method of treating pain in a subject, whereinthe subject is a first subject, in the first about 72 hours followinginjection of the pharmaceutical composition into the subarachnoid spaceof the first subject the opioid is administered to the first subject ina total amount that is lower than the total amount of an opioid that isadministered to a second subject in the first about 72 hours followinginjection into the subarachnoid space of the second subject ofnon-liposomal bupivacaine containing the same amount of bupivacaine asthe pharmaceutical composition, wherein a multivesicular liposomalparticle pharmaceutical composition of pre-determined, uniform sizedistribution, made by a process comprising: a) providing a firstemulsion by mixing a first aqueous phase and a volatile water-immisciblesolvent phase, said solvent phase comprising at least one amphipathiclipid and at least one neutral lipid; b) mixing and emulsifying saidfirst emulsion and a second aqueous phase in a mixer to provide a secondemulsion, said second emulsion comprising a continuous aqueous phase; c)sparging the volatile water-immiscible solvent from the second emulsionto form an aqueous suspension of multivesicular liposomal particles bybubbling an inert gas through the second emulsion using at least onesparge ring, at least one sparge tube or at least one fit; d) primaryfiltration of the aqueous suspension of multivesicular liposomalparticles by cross-flow filtration using a filter to exchange the secondaqueous phase with an aqueous component to provide an initial volume ofaqueous media, wherein the filter has a membrane pore size from 0.07 to0.45 μm; e) secondary filtration by cross-flow filtration to reduce theinitial volume to provide a subsequent volume of aqueous media that is10% to 90% of the initial volume, further wherein the cross-flowfiltration is carried out with a process-scale tangential flow filterwith a filtration area of 23 square feet or more, wherein all steps arecarried out under aseptic conditions, f) the composition is prepared inquantities or batches greater than a liter; wherein the first emulsionis mixed in a first emulsification vessel of at least 10 liters involume; and g) wherein the uniform size distribution has a numberweighted mean particle size of at least 10 microns, is not administeredto the second subject.

In some embodiments of the method of treating pain in a subject, whereinthe subject is a first subject, in the first about 72 hours followinginjection of the pharmaceutical composition into the subarachnoid spaceof the first subject the opioid is administered to the first subject ina total amount that is lower than the total amount of an opioid that isadministered to a second subject in the first about 72 hours followinginjection into the subarachnoid space of the second subject ofnon-liposomal bupivacaine containing the same amount of bupivacaine asthe pharmaceutical composition, wherein a composition comprisingmultivesicular liposomes comprising bupivacaine or a salt thereof andhaving a structure including multiple non-concentric chambers andcomprising at least one amphipathic lipid and at least one neutrallipid, wherein said multivesicular liposomes are made by a processcomprising removing organic solvent from multivesicular liposomespre-droplets that comprise a first component core and an aqueous phaseshell with an evaporation apparatus, the evaporation apparatuscomprising: a solvent removal vessel having a top, a bottom and acircular wall; at least one atomizing nozzle; a carrier gas entranceorifice; a solvent removal gas exit orifice centrally connected to thetop; and a product exit orifice connected to the bottom of the vessel,

wherein the process comprises: introducing the pre-droplets to thesolvent removal vessel; applying a carrier gas in a tangential directionto the circular wall through the carrier gas entrance orifice; andremoving a solvent removal gas through the solvent removal gas exitorifice to provide the large diameter synthetic membrane vesicles,

is not administered to the second subject.

DETAILED DESCRIPTION

In some embodiments provided herein is a method of treating pain in asubject, the method comprising injecting into the subarachnoid space ofthe subject a pharmaceutical composition comprising: a) a multivesicularliposome comprising: at least one amphipathic lipid, and at least oneneutral lipid; and b) an aqueous phase comprising: at least onepolyhydroxy carboxylic acid and at least one di- or tri-protic mineralacid; and bupivacaine phosphate, wherein the aqueous phase isencapsulated within the multivesicular liposome.

In some embodiments provided herein is a method of treating pain in asubject, the method comprising injecting into the subarachnoid space ofthe subject a pharmaceutical composition comprising: a) a multivesicularliposome comprising: at least one amphipathic lipid, and at least oneneutral lipid; and b) an aqueous phase comprising bupivacaine phosphate,wherein the aqueous phase is encapsulated within the multivesicularliposome.

In some embodiments provided herein is a method of treating pain in asubject, the method comprising injecting into the subarachnoid space ofthe subject a pharmaceutical composition comprising multivesicularliposomes encapsulating bupivacaine phosphate, said multivesicularliposomes comprising:

bupivacaine or a salt thereof;

phosphoric acid;

a lipid component comprising at least one amphipathic lipid and at leastone neutral lipid lacking a hydrophilic head group; and,

optionally, a cholesterol and/or a plant sterol wherein saidmultivesicular liposomes are made by a process comprising:

a) preparing a first aqueous component comprising phosphoric acid;

b) preparing a lipid component comprising at least one organic solvent,at least one amphipathic lipid, and at least one neutral lipid lacking ahydrophilic head group;

c) mixing said first aqueous component and said lipid component to forma water-in-oil emulsion, wherein at least one component comprisesbupivacaine or a salt thereof;

d) mixing said water-in-oil emulsion with a second aqueous component toform solvent spherules; and

e) removing the organic solvent from the solvent spherules to formmultivesicular liposomes encapsulating bupivacaine phosphate.

In some embodiments provided herein is a method of treating pain in asubject, the method comprising injecting into the subarachnoid space ofthe subject a multivesicular liposomal particle pharmaceuticalcomposition made by a process comprising: a) providing a volume of firstemulsion by mixing a volume of a first aqueous phase and a volume of avolatile water-immiscible solvent phase, said solvent phase comprisingat least one amphipathic lipid and at least one neutral lipid; b) mixingand emulsifying said first emulsion and a volume of a second aqueousphase in a high shear mixer to provide a volume of a second emulsion,said second emulsion comprising a continuous aqueous phase; and c)removing the volatile water-immiscible solvent from the second emulsionto form a volume of multivesicular liposomal particle composition,wherein said solvent removal comprises contacting the second emulsionwith an inert gas flow; and wherein said process further comprisesprimary filtration of the multivesicular liposomal particle compositionby cross-flow filtration using a filter having a membrane where themultivesicular liposomal particle composition does not pass through themembrane; wherein all steps are carried out under aseptic conditions,and wherein all solutions are sterile filtered, and wherein themultivesicular liposomal particle composition is immediately suitablefor administration into humans; and wherein the primary filtrationcomprises: a first concentration of the multivesicular liposomalparticle composition; and a buffer exchange, resulting in a pH of themultivesicular liposomal particle composition of between about 5 andabout 8, and the primary filtration is conducted at a transmembranepressure of from about 0.1 psi to about 20 psi, such as to about 7 psi.

In some embodiments provided herein is a method of treating pain in asubject, the method comprising injecting into the subarachnoid space ofthe subject a multivesicular liposomal particle pharmaceuticalcomposition of pre-determined, uniform size distribution, made by aprocess comprising: a) providing a first emulsion by mixing a firstaqueous phase and a volatile water-immiscible solvent phase, saidsolvent phase comprising at least one amphipathic lipid and at least oneneutral lipid; b) mixing and emulsifying said first emulsion and asecond aqueous phase in a mixer to provide a second emulsion, saidsecond emulsion comprising a continuous aqueous phase; c) sparging thevolatile water-immiscible solvent from the second emulsion to form anaqueous suspension of multivesicular liposomal particles by bubbling aninert gas through the second emulsion using at least one sparge ring, atleast one sparge tube or at least one fit; d) primary filtration of theaqueous suspension of multivesicular liposomal particles by cross-flowfiltration using a filter to exchange the second aqueous phase with anaqueous component to provide an initial volume of aqueous media, whereinthe filter has a membrane pore size from 0.07 to 0.45 μm; e) secondaryfiltration by cross-flow filtration to reduce the initial volume toprovide a subsequent volume of aqueous media that is 10% to 90% of theinitial volume, further wherein the cross-flow filtration is carried outwith a process-scale tangential flow filter with a filtration area of 23square feet or more, wherein all steps are carried out under asepticconditions, f) the composition is prepared in quantities or batchesgreater than a liter; wherein the first emulsion is mixed in a firstemulsification vessel of at least 10 liters in volume; and g) whereinthe uniform size distribution has a number weighted mean particle sizeof at least 10 microns.

In some embodiments provided herein is a method of treating pain in asubject, the method comprising injecting into the subarachnoid space ofthe subject a composition comprising multivesicular liposomes comprisingbupivacaine or a salt thereof and having a structure including multiplenon-concentric chambers and comprising at least one amphipathic lipidand at least one neutral lipid, wherein said multivesicular liposomesare made by a process comprising removing organic solvent frommultivesicular liposomes pre-droplets that comprise a first componentcore and an aqueous phase shell with an evaporation apparatus, theevaporation apparatus comprising: a solvent removal vessel having a top,a bottom and a circular wall; at least one atomizing nozzle; a carriergas entrance orifice; a solvent removal gas exit orifice centrallyconnected to the top; and a product exit orifice connected to the bottomof the vessel,

wherein the process comprises: introducing the pre-droplets to thesolvent removal vessel; applying a carrier gas in a tangential directionto the circular wall through the carrier gas entrance orifice; andremoving a solvent removal gas through the solvent removal gas exitorifice to provide the large diameter synthetic membrane vesicles.

In some embodiments provided herein is a method of anesthetizing asubject in need thereof, the method comprising injecting into thesubarachnoid space of the subject a pharmaceutical compositioncomprising: a) a multivesicular liposome comprising: at least oneamphipathic lipid, and at least one neutral lipid; and b) an aqueousphase comprising: at least one polyhydroxy carboxylic acid and at leastone di- or tri-protic mineral acid; and bupivacaine phosphate, whereinthe aqueous phase is encapsulated within the multivesicular liposome.

In some embodiments provided herein is a method of anesthetizing asubject in need thereof, the method comprising injecting into thesubarachnoid space of the subject a pharmaceutical compositioncomprising: a) a multivesicular liposome comprising: at least oneamphipathic lipid, and at least one neutral lipid; and b) an aqueousphase comprising bupivacaine phosphate, wherein the aqueous phase isencapsulated within the multivesicular liposome.

In some embodiments provided herein is a method of anesthetizing asubject in need thereof, the method comprising injecting into thesubarachnoid space of the subject a pharmaceutical compositioncomprising multivesicular liposomes encapsulating bupivacaine phosphate,said multivesicular liposomes comprising:

bupivacaine or a salt thereof;

phosphoric acid;

a lipid component comprising at least one amphipathic lipid and at leastone neutral lipid lacking a hydrophilic head group; and,

optionally, a cholesterol and/or a plant sterol wherein saidmultivesicular liposomes are made by a process comprising:

a) preparing a first aqueous component comprising phosphoric acid;

b) preparing a lipid component comprising at least one organic solvent,at least one amphipathic lipid, and at least one neutral lipid lacking ahydrophilic head group;

c) mixing said first aqueous component and said lipid component to forma water-in-oil emulsion, wherein at least one component comprisesbupivacaine or a salt thereof;

d) mixing said water-in-oil emulsion with a second aqueous component toform solvent spherules; and

e) removing the organic solvent from the solvent spherules to formmultivesicular liposomes encapsulating bupivacaine phosphate.

In some embodiments provided herein is a method of anesthetizing asubject in need thereof, the method comprising injecting into thesubarachnoid space of the subject a multivesicular liposomal particlepharmaceutical composition made by a process comprising: a) providing avolume of first emulsion by mixing a volume of a first aqueous phase anda volume of a volatile water-immiscible solvent phase, said solventphase comprising at least one amphipathic lipid and at least one neutrallipid; b) mixing and emulsifying said first emulsion and a volume of asecond aqueous phase in a high shear mixer to provide a volume of asecond emulsion, said second emulsion comprising a continuous aqueousphase; and c) removing the volatile water-immiscible solvent from thesecond emulsion to form a volume of multivesicular liposomal particlecomposition, wherein said solvent removal comprises contacting thesecond emulsion with an inert gas flow; and wherein said process furthercomprises primary filtration of the multivesicular liposomal particlecomposition by cross-flow filtration using a filter having a membranewhere the multivesicular liposomal particle composition does not passthrough the membrane; wherein all steps are carried out under asepticconditions, and wherein all solutions are sterile filtered, and whereinthe multivesicular liposomal particle composition is immediatelysuitable for administration into humans; and wherein the primaryfiltration comprises: a first concentration of the multivesicularliposomal particle composition; and a buffer exchange, resulting in a pHof the multivesicular liposomal particle composition of between about 5and about 8, and the primary filtration is conducted at a transmembranepressure of from about 0.1 psi to about 20 psi, such as to about 7 psi.

In some embodiments provided herein is a method of anesthetizing asubject in need thereof, the method comprising injecting into thesubarachnoid space of the subject a multivesicular liposomal particlepharmaceutical composition of pre-determined, uniform size distribution,made by a process comprising: a) providing a first emulsion by mixing afirst aqueous phase and a volatile water-immiscible solvent phase, saidsolvent phase comprising at least one amphipathic lipid and at least oneneutral lipid; b) mixing and emulsifying said first emulsion and asecond aqueous phase in a mixer to provide a second emulsion, saidsecond emulsion comprising a continuous aqueous phase; c) sparging thevolatile water-immiscible solvent from the second emulsion to form anaqueous suspension of multivesicular liposomal particles by bubbling aninert gas through the second emulsion using at least one sparge ring, atleast one sparge tube or at least one fit; d) primary filtration of theaqueous suspension of multivesicular liposomal particles by cross-flowfiltration using a filter to exchange the second aqueous phase with anaqueous component to provide an initial volume of aqueous media, whereinthe filter has a membrane pore size from 0.07 to 0.45 μm; e) secondaryfiltration by cross-flow filtration to reduce the initial volume toprovide a subsequent volume of aqueous media that is 10% to 90% of theinitial volume, further wherein the cross-flow filtration is carried outwith a process-scale tangential flow filter with a filtration area of 23square feet or more, wherein all steps are carried out under asepticconditions, f) the composition is prepared in quantities or batchesgreater than a liter; wherein the first emulsion is mixed in a firstemulsification vessel of at least 10 liters in volume; and g) whereinthe uniform size distribution has a number weighted mean particle sizeof at least 10 microns.

In some embodiments provided herein is a method of anesthetizing asubject in need thereof, the method comprising injecting into thesubarachnoid space of the subject a composition comprisingmultivesicular liposomes comprising bupivacaine or a salt thereof andhaving a structure including multiple non-concentric chambers andcomprising at least one amphipathic lipid and at least one neutrallipid, wherein said multivesicular liposomes are made by a processcomprising removing organic solvent from multivesicular liposomespre-droplets that comprise a first component core and an aqueous phaseshell with an evaporation apparatus, the evaporation apparatuscomprising: a solvent removal vessel having a top, a bottom and acircular wall; at least one atomizing nozzle; a carrier gas entranceorifice; a solvent removal gas exit orifice centrally connected to thetop; and a product exit orifice connected to the bottom of the vessel,

wherein the process comprises: introducing the pre-droplets to thesolvent removal vessel; applying a carrier gas in a tangential directionto the circular wall through the carrier gas entrance orifice; andremoving a solvent removal gas through the solvent removal gas exitorifice to provide the large diameter synthetic membrane vesicles.

In some embodiments provided herein is a method of reducing pain in asubject, the method comprising injecting into the subarachnoid space ofthe subject a pharmaceutical composition comprising: a) a multivesicularliposome comprising: at least one amphipathic lipid, and at least oneneutral lipid; and b) an aqueous phase comprising: at least onepolyhydroxy carboxylic acid and at least one di- or tri-protic mineralacid; and bupivacaine phosphate, wherein the aqueous phase isencapsulated within the multivesicular liposome.

In some embodiments provided herein is a method of reducing pain in asubject, the method comprising injecting into the subarachnoid space ofthe subject a pharmaceutical composition comprising: a) a multivesicularliposome comprising: at least one amphipathic lipid, and at least oneneutral lipid; and b) an aqueous phase comprising bupivacaine phosphate,wherein the aqueous phase is encapsulated within the multivesicularliposome.

In some embodiments provided herein is a method of reducing pain in asubject, the method comprising injecting into the subarachnoid space ofthe subject a pharmaceutical composition comprising multivesicularliposomes encapsulating bupivacaine phosphate, said multivesicularliposomes comprising:

bupivacaine or a salt thereof;

phosphoric acid;

a lipid component comprising at least one amphipathic lipid and at leastone neutral lipid lacking a hydrophilic head group; and,

optionally, a cholesterol and/or a plant sterol wherein saidmultivesicular liposomes are made by a process comprising:

a) preparing a first aqueous component comprising phosphoric acid;

b) preparing a lipid component comprising at least one organic solvent,at least one amphipathic lipid, and at least one neutral lipid lacking ahydrophilic head group;

c) mixing said first aqueous component and said lipid component to forma water-in-oil emulsion, wherein at least one component comprisesbupivacaine or a salt thereof;

d) mixing said water-in-oil emulsion with a second aqueous component toform solvent e) removing the organic solvent from the solvent spherulesto form multivesicular liposomes encapsulating bupivacaine phosphate.

In some embodiments provided herein is a method of reducing pain in asubject, the method comprising injecting into the subarachnoid space ofthe subject a multivesicular liposomal particle pharmaceuticalcomposition made by a process comprising: a) providing a volume of firstemulsion by mixing a volume of a first aqueous phase and a volume of avolatile water-immiscible solvent phase, said solvent phase comprisingat least one amphipathic lipid and at least one neutral lipid; b) mixingand emulsifying said first emulsion and a volume of a second aqueousphase in a high shear mixer to provide a volume of a second emulsion,said second emulsion comprising a continuous aqueous phase; and c)removing the volatile water-immiscible solvent from the second emulsionto form a volume of multivesicular liposomal particle composition,wherein said solvent removal comprises contacting the second emulsionwith an inert gas flow; and wherein said process further comprisesprimary filtration of the multivesicular liposomal particle compositionby cross-flow filtration using a filter having a membrane where themultivesicular liposomal particle composition does not pass through themembrane; wherein all steps are carried out under aseptic conditions,and wherein all solutions are sterile filtered, and wherein themultivesicular liposomal particle composition is immediately suitablefor administration into humans; and wherein the primary filtrationcomprises: a first concentration of the multivesicular liposomalparticle composition; and a buffer exchange, resulting in a pH of themultivesicular liposomal particle composition of between about 5 andabout 8, and the primary filtration is conducted at a transmembranepressure of from about 0.1 psi to about 20 psi, such as to about 7 psi.

In some embodiments provided herein is a method of reducing pain in asubject, the method comprising injecting into the subarachnoid space ofthe subject a multivesicular liposomal particle pharmaceuticalcomposition of pre-determined, uniform size distribution, made by aprocess comprising: a) providing a first emulsion by mixing a firstaqueous phase and a volatile water-immiscible solvent phase, saidsolvent phase comprising at least one amphipathic lipid and at least oneneutral lipid; b) mixing and emulsifying said first emulsion and asecond aqueous phase in a mixer to provide a second emulsion, saidsecond emulsion comprising a continuous aqueous phase; c) sparging thevolatile water-immiscible solvent from the second emulsion to form anaqueous suspension of multivesicular liposomal particles by bubbling aninert gas through the second emulsion using at least one sparge ring, atleast one sparge tube or at least one fit; d) primary filtration of theaqueous suspension of multivesicular liposomal particles by cross-flowfiltration using a filter to exchange the second aqueous phase with anaqueous component to provide an initial volume of aqueous media, whereinthe filter has a membrane pore size from 0.07 to 0.45 μm; e) secondaryfiltration by cross-flow filtration to reduce the initial volume toprovide a subsequent volume of aqueous media that is 10% to 90% of theinitial volume, further wherein the cross-flow filtration is carried outwith a process-scale tangential flow filter with a filtration area of 23square feet or more, wherein all steps are carried out under asepticconditions, f) the composition is prepared in quantities or batchesgreater than a liter; wherein the first emulsion is mixed in a firstemulsification vessel of at least 10 liters in volume; and g) whereinthe uniform size distribution has a number weighted mean particle sizeof at least 10 microns.

In some embodiments provided herein is a method of reducing pain in asubject, the method comprising injecting into the subarachnoid space ofthe subject a composition comprising multivesicular liposomes comprisingbupivacaine or a salt thereof and having a structure including multiplenon-concentric chambers and comprising at least one amphipathic lipidand at least one neutral lipid, wherein said multivesicular liposomesare made by a process comprising removing organic solvent frommultivesicular liposomes pre-droplets that comprise a first componentcore and an aqueous phase shell with an evaporation apparatus, theevaporation apparatus comprising: a solvent removal vessel having a top,a bottom and a circular wall; at least one atomizing nozzle; a carriergas entrance orifice; a solvent removal gas exit orifice centrallyconnected to the top; and a product exit orifice connected to the bottomof the vessel,

wherein the process comprises: introducing the pre-droplets to thesolvent removal vessel; applying a carrier gas in a tangential directionto the circular wall through the carrier gas entrance orifice; andremoving a solvent removal gas through the solvent removal gas exitorifice to provide the large diameter synthetic membrane vesicles.

In some embodiments provided herein is a method of reducing an amount ofan analgesic, such as an opioid, administered to a subject in needthereof, the method comprising injecting into the subarachnoid space ofthe subject a pharmaceutical composition comprising: a) a multivesicularliposome comprising: at least one amphipathic lipid, and at least oneneutral lipid; and b) an aqueous phase comprising: at least onepolyhydroxy carboxylic acid and at least one di- or tri-protic mineralacid; and bupivacaine phosphate, wherein the aqueous phase isencapsulated within the multivesicular liposome.

In some embodiments provided herein is a method of reducing an amount ofan analgesic, such as an opioid, administered to a subject in needthereof, the method comprising injecting into the subarachnoid space ofthe subject a pharmaceutical composition comprising: a) a multivesicularliposome comprising: at least one amphipathic lipid, and at least oneneutral lipid; and b) an aqueous phase comprising bupivacaine phosphate,wherein the aqueous phase is encapsulated within the multivesicularliposome.

In some embodiments provided herein is a method of reducing an amount ofan analgesic, such as an opioid, administered to a subject in needthereof, the method comprising injecting into the subarachnoid space ofthe subject a pharmaceutical composition comprising multivesicularliposomes encapsulating bupivacaine phosphate, said multivesicularliposomes comprising:

bupivacaine or a salt thereof;

phosphoric acid;

a lipid component comprising at least one amphipathic lipid and at leastone neutral lipid lacking a hydrophilic head group; and,

optionally, a cholesterol and/or a plant sterol wherein saidmultivesicular liposomes are made by a process comprising:

a) preparing a first aqueous component comprising phosphoric acid;

b) preparing a lipid component comprising at least one organic solvent,at least one amphipathic lipid, and at least one neutral lipid lacking ahydrophilic head group;

c) mixing said first aqueous component and said lipid component to forma water-in-oil emulsion, wherein at least one component comprisesbupivacaine or a salt thereof;

d) mixing said water-in-oil emulsion with a second aqueous component toform solvent spherules; and

e) removing the organic solvent from the solvent spherules to formmultivesicular liposomes encapsulating bupivacaine phosphate.

In some embodiments provided herein is a method of reducing an amount ofan analgesic, such as an opioid, administered to a subject in needthereof, the method comprising injecting into the subarachnoid space ofthe subject a multivesicular liposomal particle pharmaceuticalcomposition made by a process comprising: a) providing a volume of firstemulsion by mixing a volume of a first aqueous phase and a volume of avolatile water-immiscible solvent phase, said solvent phase comprisingat least one amphipathic lipid and at least one neutral lipid; b) mixingand emulsifying said first emulsion and a volume of a second aqueousphase in a high shear mixer to provide a volume of a second emulsion,said second emulsion comprising a continuous aqueous phase; and c)removing the volatile water-immiscible solvent from the second emulsionto form a volume of multivesicular liposomal particle composition,wherein said solvent removal comprises contacting the second emulsionwith an inert gas flow; and wherein said process further comprisesprimary filtration of the multivesicular liposomal particle compositionby cross-flow filtration using a filter having a membrane where themultivesicular liposomal particle composition does not pass through themembrane; wherein all steps are carried out under aseptic conditions,and wherein all solutions are sterile filtered, and wherein themultivesicular liposomal particle composition is immediately suitablefor administration into humans; and wherein the primary filtrationcomprises: a first concentration of the multivesicular liposomalparticle composition; and a buffer exchange, resulting in a pH of themultivesicular liposomal particle composition of between about 5 andabout 8, and the primary filtration is conducted at a transmembranepressure of from about 0.1 psi to about 20 psi, such as to about 7 psi.

In some embodiments provided herein is a method of reducing an amount ofan analgesic, such as an opioid, administered to a subject in needthereof, the method comprising injecting into the subarachnoid space ofthe subject a multivesicular liposomal particle pharmaceuticalcomposition of pre-determined, uniform size distribution, made by aprocess comprising: a) providing a first emulsion by mixing a firstaqueous phase and a volatile water-immiscible solvent phase, saidsolvent phase comprising at least one amphipathic lipid and at least oneneutral lipid; b) mixing and emulsifying said first emulsion and asecond aqueous phase in a mixer to provide a second emulsion, saidsecond emulsion comprising a continuous aqueous phase; c) sparging thevolatile water-immiscible solvent from the second emulsion to form anaqueous suspension of multivesicular liposomal particles by bubbling aninert gas through the second emulsion using at least one sparge ring, atleast one sparge tube or at least one fit; d) primary filtration of theaqueous suspension of multivesicular liposomal particles by cross-flowfiltration using a filter to exchange the second aqueous phase with anaqueous component to provide an initial volume of aqueous media, whereinthe filter has a membrane pore size from 0.07 to 0.45 μm; e) secondaryfiltration by cross-flow filtration to reduce the initial volume toprovide a subsequent volume of aqueous media that is 10% to 90% of theinitial volume, further wherein the cross-flow filtration is carried outwith a process-scale tangential flow filter with a filtration area of 23square feet or more, wherein all steps are carried out under asepticconditions, f) the composition is prepared in quantities or batchesgreater than a liter; wherein the first emulsion is mixed in a firstemulsification vessel of at least 10 liters in volume; and g) whereinthe uniform size distribution has a number weighted mean particle sizeof at least 10 microns.

In some embodiments provided herein is a method of reducing an amount ofan analgesic, such as an opioid, administered to a subject in needthereof, the method comprising injecting into the subarachnoid space ofthe subject a composition comprising multivesicular liposomes comprisingbupivacaine or a salt thereof and having a structure including multiplenon-concentric chambers and comprising at least one amphipathic lipidand at least one neutral lipid, wherein said multivesicular liposomesare made by a process comprising removing organic solvent frommultivesicular liposomes pre-droplets that comprise a first componentcore and an aqueous phase shell with an evaporation apparatus, theevaporation apparatus comprising: a solvent removal vessel having a top,a bottom and a circular wall; at least one atomizing nozzle; a carriergas entrance orifice; a solvent removal gas exit orifice centrallyconnected to the top; and a product exit orifice connected to the bottomof the vessel,

wherein the process comprises: introducing the pre-droplets to thesolvent removal vessel; applying a carrier gas in a tangential directionto the circular wall through the carrier gas entrance orifice; andremoving a solvent removal gas through the solvent removal gas exitorifice to provide the large diameter synthetic membrane vesicles.

In some more particular embodiments of the methods where the analgesic,such as an opioid, is administered to the subject, the analgesic isadministered following a surgical procedure in the subject. In someembodiments the analgesic reduces pain in the subject following thesurgical procedure.

In some embodiments provided herein is a method of reducing a durationof time during which an analgesic, such as an opioid, is administered toa subject in need thereof, the method comprising injecting into thesubarachnoid space of the subject a pharmaceutical compositioncomprising: a) a multivesicular liposome comprising: at least oneamphipathic lipid, and at least one neutral lipid; and b) an aqueousphase comprising: at least one polyhydroxy carboxylic acid and at leastone di- or tri-protic mineral acid; and bupivacaine phosphate, whereinthe aqueous phase is encapsulated within the multivesicular liposome.

In some embodiments provided herein is a method of reducing a durationof time during which an analgesic, such as an opioid, is administered toa subject in need thereof, the method comprising injecting into thesubarachnoid space of the subject a pharmaceutical compositioncomprising: a) a multivesicular liposome comprising: at least oneamphipathic lipid, and at least one neutral lipid; and b) an aqueousphase comprising bupivacaine phosphate, wherein the aqueous phase isencapsulated within the multivesicular liposome.

In some embodiments provided herein is a method of reducing a durationof time during which an analgesic, such as an opioid, is administered toa subject in need thereof, the method comprising injecting into thesubarachnoid space of the subject a pharmaceutical compositioncomprising multivesicular liposomes encapsulating bupivacaine phosphate,said multivesicular liposomes comprising:

bupivacaine or a salt thereof;

phosphoric acid;

a lipid component comprising at least one amphipathic lipid and at leastone neutral lipid lacking a hydrophilic head group; and,

optionally, a cholesterol and/or a plant sterol wherein saidmultivesicular liposomes are made by a process comprising:

a) preparing a first aqueous component comprising phosphoric acid;

b) preparing a lipid component comprising at least one organic solvent,at least one amphipathic lipid, and at least one neutral lipid lacking ahydrophilic head group;

c) mixing said first aqueous component and said lipid component to forma water-in-oil emulsion, wherein at least one component comprisesbupivacaine or a salt thereof;

d) mixing said water-in-oil emulsion with a second aqueous component toform solvent spherules; and

e) removing the organic solvent from the solvent spherules to formmultivesicular liposomes encapsulating bupivacaine phosphate.

In some embodiments provided herein is a method of reducing a durationof time during which an analgesic, such as an opioid, is administered toa subject in need thereof, the method comprising injecting into thesubarachnoid space of the subject a multivesicular liposomal particlepharmaceutical composition made by a process comprising: a) providing avolume of first emulsion by mixing a volume of a first aqueous phase anda volume of a volatile water-immiscible solvent phase, said solventphase comprising at least one amphipathic lipid and at least one neutrallipid; b) mixing and emulsifying said first emulsion and a volume of asecond aqueous phase in a high shear mixer to provide a volume of asecond emulsion, said second emulsion comprising a continuous aqueousphase; and c) removing the volatile water-immiscible solvent from thesecond emulsion to form a volume of multivesicular liposomal particlecomposition, wherein said solvent removal comprises contacting thesecond emulsion with an inert gas flow; and wherein said process furthercomprises primary filtration of the multivesicular liposomal particlecomposition by cross-flow filtration using a filter having a membranewhere the multivesicular liposomal particle composition does not passthrough the membrane; wherein all steps are carried out under asepticconditions, and wherein all solutions are sterile filtered, and whereinthe multivesicular liposomal particle composition is immediatelysuitable for administration into humans; and wherein the primaryfiltration comprises: a first concentration of the multivesicularliposomal particle composition; and a buffer exchange, resulting in a pHof the multivesicular liposomal particle composition of between about 5and about 8, and the primary filtration is conducted at a transmembranepressure of from about 0.1 psi to about 20 psi, such as to about 7 psi.

In some embodiments provided herein is a method of reducing a durationof time during which an analgesic, such as an opioid, is administered toa subject in need thereof, the method comprising injecting into thesubarachnoid space of the subject a multivesicular liposomal particlepharmaceutical composition of pre-determined, uniform size distribution,made by a process comprising: a) providing a first emulsion by mixing afirst aqueous phase and a volatile water-immiscible solvent phase, saidsolvent phase comprising at least one amphipathic lipid and at least oneneutral lipid; b) mixing and emulsifying said first emulsion and asecond aqueous phase in a mixer to provide a second emulsion, saidsecond emulsion comprising a continuous aqueous phase; c) sparging thevolatile water-immiscible solvent from the second emulsion to form anaqueous suspension of multivesicular liposomal particles by bubbling aninert gas through the second emulsion using at least one sparge ring, atleast one sparge tube or at least one fit; d) primary filtration of theaqueous suspension of multivesicular liposomal particles by cross-flowfiltration using a filter to exchange the second aqueous phase with anaqueous component to provide an initial volume of aqueous media, whereinthe filter has a membrane pore size from 0.07 to 0.45 μm; e) secondaryfiltration by cross-flow filtration to reduce the initial volume toprovide a subsequent volume of aqueous media that is 10% to 90% of theinitial volume, further wherein the cross-flow filtration is carried outwith a process-scale tangential flow filter with a filtration area of 23square feet or more, wherein all steps are carried out under asepticconditions, f) the composition is prepared in quantities or batchesgreater than a liter; wherein the first emulsion is mixed in a firstemulsification vessel of at least 10 liters in volume; and g) whereinthe uniform size distribution has a number weighted mean particle sizeof at least 10 microns.

In some embodiments provided herein is a method of reducing a durationof time during which an analgesic, such as an opioid, is administered toa subject in need thereof, the method comprising injecting into thesubarachnoid space of the subject a composition comprisingmultivesicular liposomes comprising bupivacaine or a salt thereof andhaving a structure including multiple non-concentric chambers andcomprising at least one amphipathic lipid and at least one neutrallipid, wherein said multivesicular liposomes are made by a processcomprising removing organic solvent from multivesicular liposomespre-droplets that comprise a first component core and an aqueous phaseshell with an evaporation apparatus, the evaporation apparatuscomprising: a solvent removal vessel having a top, a bottom and acircular wall; at least one atomizing nozzle; a carrier gas entranceorifice; a solvent removal gas exit orifice centrally connected to thetop; and a product exit orifice connected to the bottom of the vessel,

wherein the process comprises: introducing the pre-droplets to thesolvent removal vessel; applying a carrier gas in a tangential directionto the circular wall through the carrier gas entrance orifice; andremoving a solvent removal gas through the solvent removal gas exitorifice to provide the large diameter synthetic membrane vesicles.

In some more particular embodiments of the methods where the analgesic,such as an opioid, is administered to the subject, the analgesic isadministered following a surgical procedure in the subject. In someembodiments the analgesic reduces pain in the subject following thesurgical procedure.

In some embodiments provided herein is a method of reducing an amount ofa non-opioid analgesic administered to a subject in need thereof, themethod comprising injecting into the subarachnoid space of the subject apharmaceutical composition comprising: a) a multivesicular liposomecomprising: at least one amphipathic lipid, and at least one neutrallipid; and b) an aqueous phase comprising: at least one polyhydroxycarboxylic acid and at least one di- or tri-protic mineral acid; andbupivacaine phosphate, wherein the aqueous phase is encapsulated withinthe multivesicular liposome.

In some embodiments provided herein is a method of reducing an amount ofa non-opioid analgesic administered to a subject in need thereof, themethod comprising injecting into the subarachnoid space of the subject apharmaceutical composition comprising: a) a multivesicular liposomecomprising: at least one amphipathic lipid, and at least one neutrallipid; and b) an aqueous phase comprising bupivacaine phosphate, whereinthe aqueous phase is encapsulated within the multivesicular liposome.

In some embodiments provided herein is a method of reducing an amount ofa non-opioid analgesic administered to a subject in need thereof, themethod comprising injecting into the subarachnoid space of the subject apharmaceutical composition comprising multivesicular liposomesencapsulating bupivacaine phosphate, said multivesicular liposomescomprising:

bupivacaine or a salt thereof;

phosphoric acid;

a lipid component comprising at least one amphipathic lipid and at leastone neutral lipid lacking a hydrophilic head group; and,

optionally, a cholesterol and/or a plant sterol wherein saidmultivesicular liposomes are made by a process comprising:

a) preparing a first aqueous component comprising phosphoric acid;

b) preparing a lipid component comprising at least one organic solvent,at least one amphipathic lipid, and at least one neutral lipid lacking ahydrophilic head group;

c) mixing said first aqueous component and said lipid component to forma water-in-oil emulsion, wherein at least one component comprisesbupivacaine or a salt thereof;

d) mixing said water-in-oil emulsion with a second aqueous component toform solvent spherules; and

e) removing the organic solvent from the solvent spherules to formmultivesicular liposomes encapsulating bupivacaine phosphate.

In some embodiments provided herein is a method of reducing an amount ofa non-opioid analgesic administered to a subject in need thereof, themethod comprising injecting into the subarachnoid space of the subject amultivesicular liposomal particle pharmaceutical composition made by aprocess comprising: a) providing a volume of first emulsion by mixing avolume of a first aqueous phase and a volume of a volatilewater-immiscible solvent phase, said solvent phase comprising at leastone amphipathic lipid and at least one neutral lipid; b) mixing andemulsifying said first emulsion and a volume of a second aqueous phasein a high shear mixer to provide a volume of a second emulsion, saidsecond emulsion comprising a continuous aqueous phase; and c) removingthe volatile water-immiscible solvent from the second emulsion to form avolume of multivesicular liposomal particle composition, wherein saidsolvent removal comprises contacting the second emulsion with an inertgas flow; and wherein said process further comprises primary filtrationof the multivesicular liposomal particle composition by cross-flowfiltration using a filter having a membrane where the multivesicularliposomal particle composition does not pass through the membrane;wherein all steps are carried out under aseptic conditions, and whereinall solutions are sterile filtered, and wherein the multivesicularliposomal particle composition is immediately suitable foradministration into humans; and wherein the primary filtrationcomprises: a first concentration of the multivesicular liposomalparticle composition; and a buffer exchange, resulting in a pH of themultivesicular liposomal particle composition of between about 5 andabout 8, and the primary filtration is conducted at a transmembranepressure of from about 0.1 psi to about 20 psi, such as to about 7 psi.

In some embodiments provided herein is a method of reducing an amount ofa non-opioid analgesic administered to a subject in need thereof, themethod comprising injecting into the subarachnoid space of the subject amultivesicular liposomal particle pharmaceutical composition ofpre-determined, uniform size distribution, made by a process comprising:a) providing a first emulsion by mixing a first aqueous phase and avolatile water-immiscible solvent phase, said solvent phase comprisingat least one amphipathic lipid and at least one neutral lipid; b) mixingand emulsifying said first emulsion and a second aqueous phase in amixer to provide a second emulsion, said second emulsion comprising acontinuous aqueous phase; c) sparging the volatile water-immisciblesolvent from the second emulsion to form an aqueous suspension ofmultivesicular liposomal particles by bubbling an inert gas through thesecond emulsion using at least one sparge ring, at least one sparge tubeor at least one fit; d) primary filtration of the aqueous suspension ofmultivesicular liposomal particles by cross-flow filtration using afilter to exchange the second aqueous phase with an aqueous component toprovide an initial volume of aqueous media, wherein the filter has amembrane pore size from 0.07 to 0.45 μm; e) secondary filtration bycross-flow filtration to reduce the initial volume to provide asubsequent volume of aqueous media that is 10% to 90% of the initialvolume, further wherein the cross-flow filtration is carried out with aprocess-scale tangential flow filter with a filtration area of 23 squarefeet or more, wherein all steps are carried out under asepticconditions, f) the composition is prepared in quantities or batchesgreater than a liter; wherein the first emulsion is mixed in a firstemulsification vessel of at least 10 liters in volume; and g) whereinthe uniform size distribution has a number weighted mean particle sizeof at least 10 microns.

In some embodiments provided herein is a method of reducing an amount ofa non-opioid analgesic administered to a subject in need thereof, themethod comprising injecting into the subarachnoid space of the subject acomposition comprising multivesicular liposomes comprising bupivacaineor a salt thereof and having a structure including multiplenon-concentric chambers and comprising at least one amphipathic lipidand at least one neutral lipid, wherein said multivesicular liposomesare made by a process comprising removing organic solvent frommultivesicular liposomes pre-droplets that comprise a first componentcore and an aqueous phase shell with an evaporation apparatus, theevaporation apparatus comprising: a solvent removal vessel having a top,a bottom and a circular wall; at least one atomizing nozzle; a carriergas entrance orifice; a solvent removal gas exit orifice centrallyconnected to the top; and a product exit orifice connected to the bottomof the vessel,

wherein the process comprises: introducing the pre-droplets to thesolvent removal vessel; applying a carrier gas in a tangential directionto the circular wall through the carrier gas entrance orifice; andremoving a solvent removal gas through the solvent removal gas exitorifice to provide the large diameter synthetic membrane vesicles.

In some more particular embodiments of the methods where the non-opioidanalgesic is administered to the subject, the non-opioid analgesic isadministered following a surgical procedure in the subject. In someembodiments the non-opioid analgesic reduces pain in the subjectfollowing the surgical procedure.

In some embodiments provided herein is a method of reducing a durationof time during which a non-opioid analgesic is administered to a subjectin need thereof, the method comprising injecting into the subarachnoidspace of the subject a pharmaceutical composition comprising: a) amultivesicular liposome comprising: at least one amphipathic lipid, andat least one neutral lipid; and b) an aqueous phase comprising: at leastone polyhydroxy carboxylic acid and at least one di- or tri-proticmineral acid; and bupivacaine phosphate, wherein the aqueous phase isencapsulated within the multivesicular liposome.

In some embodiments provided herein is a method of reducing a durationof time during which a non-opioid analgesic is administered to a subjectin need thereof, the method comprising injecting into the subarachnoidspace of the subject a pharmaceutical composition comprising: a) amultivesicular liposome comprising: at least one amphipathic lipid, andat least one neutral lipid; and b) an aqueous phase comprisingbupivacaine phosphate, wherein the aqueous phase is encapsulated withinthe multivesicular liposome.

In some embodiments provided herein is a method of reducing a durationof time during which a non-opioid analgesic is administered to a subjectin need thereof, the method comprising injecting into the subarachnoidspace of the subject a pharmaceutical composition comprisingmultivesicular liposomes encapsulating bupivacaine phosphate, saidmultivesicular liposomes comprising:

bupivacaine or a salt thereof;

phosphoric acid;

a lipid component comprising at least one amphipathic lipid and at leastone neutral lipid lacking a hydrophilic head group; and,

optionally, a cholesterol and/or a plant sterol wherein saidmultivesicular liposomes are made by a process comprising:

a) preparing a first aqueous component comprising phosphoric acid;

b) preparing a lipid component comprising at least one organic solvent,at least one amphipathic lipid, and at least one neutral lipid lacking ahydrophilic head group;

c) mixing said first aqueous component and said lipid component to forma water-in-oil emulsion, wherein at least one component comprisesbupivacaine or a salt thereof;

d) mixing said water-in-oil emulsion with a second aqueous component toform solvent spherules; and

e) removing the organic solvent from the solvent spherules to formmultivesicular liposomes encapsulating bupivacaine phosphate.

In some embodiments provided herein is a method of reducing a durationof time during which a non-opioid analgesic is administered to a subjectin need thereof, the method comprising injecting into the subarachnoidspace of the subject a multivesicular liposomal particle pharmaceuticalcomposition made by a process comprising: a) providing a volume of firstemulsion by mixing a volume of a first aqueous phase and a volume of avolatile water-immiscible solvent phase, said solvent phase comprisingat least one amphipathic lipid and at least one neutral lipid; b) mixingand emulsifying said first emulsion and a volume of a second aqueousphase in a high shear mixer to provide a volume of a second emulsion,said second emulsion comprising a continuous aqueous phase; and c)removing the volatile water-immiscible solvent from the second emulsionto form a volume of multivesicular liposomal particle composition,wherein said solvent removal comprises contacting the second emulsionwith an inert gas flow; and wherein said process further comprisesprimary filtration of the multivesicular liposomal particle compositionby cross-flow filtration using a filter having a membrane where themultivesicular liposomal particle composition does not pass through themembrane; wherein all steps are carried out under aseptic conditions,and wherein all solutions are sterile filtered, and wherein themultivesicular liposomal particle composition is immediately suitablefor administration into humans; and wherein the primary filtrationcomprises: a first concentration of the multivesicular liposomalparticle composition; and a buffer exchange, resulting in a pH of themultivesicular liposomal particle composition of between about 5 andabout 8, and the primary filtration is conducted at a transmembranepressure of from about 0.1 psi to about 20 psi, such as to about 7 psi.

In some embodiments provided herein is a method of reducing a durationof time during which a non-opioid analgesic is administered to a subjectin need thereof, the method comprising injecting into the subarachnoidspace of the subject a multivesicular liposomal particle pharmaceuticalcomposition of pre-determined, uniform size distribution, made by aprocess comprising: a) providing a first emulsion by mixing a firstaqueous phase and a volatile water-immiscible solvent phase, saidsolvent phase comprising at least one amphipathic lipid and at least oneneutral lipid; b) mixing and emulsifying said first emulsion and asecond aqueous phase in a mixer to provide a second emulsion, saidsecond emulsion comprising a continuous aqueous phase; c) sparging thevolatile water-immiscible solvent from the second emulsion to form anaqueous suspension of multivesicular liposomal particles by bubbling aninert gas through the second emulsion using at least one sparge ring, atleast one sparge tube or at least one fit; d) primary filtration of theaqueous suspension of multivesicular liposomal particles by cross-flowfiltration using a filter to exchange the second aqueous phase with anaqueous component to provide an initial volume of aqueous media, whereinthe filter has a membrane pore size from 0.07 to 0.45 μm; e) secondaryfiltration by cross-flow filtration to reduce the initial volume toprovide a subsequent volume of aqueous media that is 10% to 90% of theinitial volume, further wherein the cross-flow filtration is carried outwith a process-scale tangential flow filter with a filtration area of 23square feet or more, wherein all steps are carried out under asepticconditions, f) the composition is prepared in quantities or batchesgreater than a liter; wherein the first emulsion is mixed in a firstemulsification vessel of at least 10 liters in volume; and g) whereinthe uniform size distribution has a number weighted mean particle sizeof at least 10 microns.

In some embodiments provided herein is a method of reducing a durationof time during which a non-opioid analgesic is administered to a subjectin need thereof, the method comprising injecting into the subarachnoidspace of the subject a composition comprising multivesicular liposomescomprising bupivacaine or a salt thereof and having a structureincluding multiple non-concentric chambers and comprising at least oneamphipathic lipid and at least one neutral lipid, wherein saidmultivesicular liposomes are made by a process comprising removingorganic solvent from multivesicular liposomes pre-droplets that comprisea first component core and an aqueous phase shell with an evaporationapparatus, the evaporation apparatus comprising: a solvent removalvessel having a top, a bottom and a circular wall; at least oneatomizing nozzle; a carrier gas entrance orifice; a solvent removal gasexit orifice centrally connected to the top; and a product exit orificeconnected to the bottom of the vessel,

wherein the process comprises: introducing the pre-droplets to thesolvent removal vessel; applying a carrier gas in a tangential directionto the circular wall through the carrier gas entrance orifice; andremoving a solvent removal gas through the solvent removal gas exitorifice to provide the large diameter synthetic membrane vesicles.

In some more particular embodiments of the methods where the non-opioidanalgesic is administered to the subject, the non-opioid analgesic isadministered following a surgical procedure in the subject. In someembodiments the non-opioid analgesic reduces pain in the subjectfollowing the surgical procedure.

In some embodiments provided herein is a method of inducing motor blockin a subject, the method comprising injecting into the subarachnoidspace of the subject a pharmaceutical composition comprising: a) amultivesicular liposome comprising: at least one amphipathic lipid, andat least one neutral lipid; and b) an aqueous phase comprising: at leastone polyhydroxy carboxylic acid and at least one di- or tri-proticmineral acid; and bupivacaine phosphate, wherein the aqueous phase isencapsulated within the multivesicular liposome.

In some embodiments provided herein is a method of inducing motor blockin a subject, the method comprising injecting into the subarachnoidspace of the subject a pharmaceutical composition comprising: a) amultivesicular liposome comprising: at least one amphipathic lipid, andat least one neutral lipid; and b) an aqueous phase comprisingbupivacaine phosphate, wherein the aqueous phase is encapsulated withinthe multivesicular liposome.

In some embodiments provided herein is a method of inducing motor blockin a subject, the method comprising injecting into the subarachnoidspace of the subject a pharmaceutical composition comprisingmultivesicular liposomes encapsulating bupivacaine phosphate, saidmultivesicular liposomes comprising:

bupivacaine or a salt thereof;

phosphoric acid;

a lipid component comprising at least one amphipathic lipid and at leastone neutral lipid lacking a hydrophilic head group; and,

optionally, a cholesterol and/or a plant sterol wherein saidmultivesicular liposomes are made by a process comprising:

a) preparing a first aqueous component comprising phosphoric acid;

b) preparing a lipid component comprising at least one organic solvent,at least one amphipathic lipid, and at least one neutral lipid lacking ahydrophilic head group;

c) mixing said first aqueous component and said lipid component to forma water-in-oil emulsion, wherein at least one component comprisesbupivacaine or a salt thereof;

d) mixing said water-in-oil emulsion with a second aqueous component toform solvent spherules; and

e) removing the organic solvent from the solvent spherules to formmultivesicular liposomes encapsulating bupivacaine phosphate.

In some embodiments provided herein is a method of inducing motor blockin a subject, the method comprising injecting into the subarachnoidspace of the subject a multivesicular liposomal particle pharmaceuticalcomposition made by a process comprising: a) providing a volume of firstemulsion by mixing a volume of a first aqueous phase and a volume of avolatile water-immiscible solvent phase, said solvent phase comprisingat least one amphipathic lipid and at least one neutral lipid; b) mixingand emulsifying said first emulsion and a volume of a second aqueousphase in a high shear mixer to provide a volume of a second emulsion,said second emulsion comprising a continuous aqueous phase; and c)removing the volatile water-immiscible solvent from the second emulsionto form a volume of multivesicular liposomal particle composition,wherein said solvent removal comprises contacting the second emulsionwith an inert gas flow; and wherein said process further comprisesprimary filtration of the multivesicular liposomal particle compositionby cross-flow filtration using a filter having a membrane where themultivesicular liposomal particle composition does not pass through themembrane; wherein all steps are carried out under aseptic conditions,and wherein all solutions are sterile filtered, and wherein themultivesicular liposomal particle composition is immediately suitablefor administration into humans; and wherein the primary filtrationcomprises: a first concentration of the multivesicular liposomalparticle composition; and a buffer exchange, resulting in a pH of themultivesicular liposomal particle composition of between about 5 andabout 8, and the primary filtration is conducted at a transmembranepressure of from about 0.1 psi to about 20 psi, such as to about 7 psi.

In some embodiments provided herein is a method of inducing motor blockin a subject, the method comprising injecting into the subarachnoidspace of the subject a multivesicular liposomal particle pharmaceuticalcomposition of pre-determined, uniform size distribution, made by aprocess comprising: a) providing a first emulsion by mixing a firstaqueous phase and a volatile water-immiscible solvent phase, saidsolvent phase comprising at least one amphipathic lipid and at least oneneutral lipid; b) mixing and emulsifying said first emulsion and asecond aqueous phase in a mixer to provide a second emulsion, saidsecond emulsion comprising a continuous aqueous phase; c) sparging thevolatile water-immiscible solvent from the second emulsion to form anaqueous suspension of multivesicular liposomal particles by bubbling aninert gas through the second emulsion using at least one sparge ring, atleast one sparge tube or at least one fit; d) primary filtration of theaqueous suspension of multivesicular liposomal particles by cross-flowfiltration using a filter to exchange the second aqueous phase with anaqueous component to provide an initial volume of aqueous media, whereinthe filter has a membrane pore size from 0.07 to 0.45 μm; e) secondaryfiltration by cross-flow filtration to reduce the initial volume toprovide a subsequent volume of aqueous media that is 10% to 90% of theinitial volume, further wherein the cross-flow filtration is carried outwith a process-scale tangential flow filter with a filtration area of 23square feet or more, wherein all steps are carried out under asepticconditions, f) the composition is prepared in quantities or batchesgreater than a liter; wherein the first emulsion is mixed in a firstemulsification vessel of at least 10 liters in volume; and g) whereinthe uniform size distribution has a number weighted mean particle sizeof at least 10 microns.

In some embodiments provided herein is a method of inducing motor blockin a subject, the method comprising injecting into the subarachnoidspace of the subject a composition comprising multivesicular liposomescomprising bupivacaine or a salt thereof and having a structureincluding multiple non-concentric chambers and comprising at least oneamphipathic lipid and at least one neutral lipid, wherein saidmultivesicular liposomes are made by a process comprising removingorganic solvent from multivesicular liposomes pre-droplets that comprisea first component core and an aqueous phase shell with an evaporationapparatus, the evaporation apparatus comprising: a solvent removalvessel having a top, a bottom and a circular wall; at least oneatomizing nozzle; a carrier gas entrance orifice; a solvent removal gasexit orifice centrally connected to the top; and a product exit orificeconnected to the bottom of the vessel,

wherein the process comprises: introducing the pre-droplets to thesolvent removal vessel; applying a carrier gas in a tangential directionto the circular wall through the carrier gas entrance orifice; andremoving a solvent removal gas through the solvent removal gas exitorifice to provide the large diameter synthetic membrane vesicles.

In some embodiments, the motor block has a shorter duration than themotor block induced by injecting into the subarachnoid space of thesubject non-liposomal bupivacaine containing the same amount ofbupivacaine as the pharmaceutical composition disclosed herein. In someembodiments, injecting into the subarachnoid space of the subject apharmaceutical composition as disclosed herein induces a motor blockhaving a duration of about 12 hours or less, or from about 12 hours toabout 24 hours, or from about 24 hours to about 48 hours, or from about48 hours to about 72 hours.

In some embodiments provided herein is a method of inducing sensoryblock in a subject, the method comprising injecting into thesubarachnoid space of the subject a pharmaceutical compositioncomprising: a) a multivesicular liposome comprising: at least oneamphipathic lipid, and at least one neutral lipid; and b) an aqueousphase comprising: at least one polyhydroxy carboxylic acid and at leastone di- or tri-protic mineral acid; and bupivacaine phosphate, whereinthe aqueous phase is encapsulated within the multivesicular liposome.

In some embodiments provided herein is a method of inducing sensoryblock in a subject, the method comprising injecting into thesubarachnoid space of the subject a pharmaceutical compositioncomprising: a) a multivesicular liposome comprising: at least oneamphipathic lipid, and at least one neutral lipid; and b) an aqueousphase comprising bupivacaine phosphate, wherein the aqueous phase isencapsulated within the multivesicular liposome.

In some embodiments provided herein is a method of inducing sensoryblock in a subject, the method comprising injecting into thesubarachnoid space of the subject a pharmaceutical compositioncomprising multivesicular liposomes encapsulating bupivacaine phosphate,said multivesicular liposomes comprising:

bupivacaine or a salt thereof;

phosphoric acid;

a lipid component comprising at least one amphipathic lipid and at leastone neutral lipid lacking a hydrophilic head group; and,

optionally, a cholesterol and/or a plant sterol wherein saidmultivesicular liposomes are made by a process comprising:

a) preparing a first aqueous component comprising phosphoric acid;

b) preparing a lipid component comprising at least one organic solvent,at least one amphipathic lipid, and at least one neutral lipid lacking ahydrophilic head group;

c) mixing said first aqueous component and said lipid component to forma water-in-oil emulsion, wherein at least one component comprisesbupivacaine or a salt thereof;

d) mixing said water-in-oil emulsion with a second aqueous component toform solvent spherules; and

e) removing the organic solvent from the solvent spherules to formmultivesicular liposomes encapsulating bupivacaine phosphate.

In some embodiments provided herein is a method of inducing sensoryblock in a subject, the method comprising injecting into thesubarachnoid space of the subject a multivesicular liposomal particlepharmaceutical composition made by a process comprising: a) providing avolume of first emulsion by mixing a volume of a first aqueous phase anda volume of a volatile water-immiscible solvent phase, said solventphase comprising at least one amphipathic lipid and at least one neutrallipid; b) mixing and emulsifying said first emulsion and a volume of asecond aqueous phase in a high shear mixer to provide a volume of asecond emulsion, said second emulsion comprising a continuous aqueousphase; and c) removing the volatile water-immiscible solvent from thesecond emulsion to form a volume of multivesicular liposomal particlecomposition, wherein said solvent removal comprises contacting thesecond emulsion with an inert gas flow; and wherein said process furthercomprises primary filtration of the multivesicular liposomal particlecomposition by cross-flow filtration using a filter having a membranewhere the multivesicular liposomal particle composition does not passthrough the membrane; wherein all steps are carried out under asepticconditions, and wherein all solutions are sterile filtered, and whereinthe multivesicular liposomal particle composition is immediatelysuitable for administration into humans; and wherein the primaryfiltration comprises: a first concentration of the multivesicularliposomal particle composition; and a buffer exchange, resulting in a pHof the multivesicular liposomal particle composition of between about 5and about 8, and the primary filtration is conducted at a transmembranepressure of from about 0.1 psi to about 20 psi, such as to about 7 psi.

In some embodiments provided herein is a method of inducing sensoryblock in a subject, the method comprising injecting into thesubarachnoid space of the subject a multivesicular liposomal particlepharmaceutical composition of pre-determined, uniform size distribution,made by a process comprising: a) providing a first emulsion by mixing afirst aqueous phase and a volatile water-immiscible solvent phase, saidsolvent phase comprising at least one amphipathic lipid and at least oneneutral lipid; b) mixing and emulsifying said first emulsion and asecond aqueous phase in a mixer to provide a second emulsion, saidsecond emulsion comprising a continuous aqueous phase; c) sparging thevolatile water-immiscible solvent from the second emulsion to form anaqueous suspension of multivesicular liposomal particles by bubbling aninert gas through the second emulsion using at least one sparge ring, atleast one sparge tube or at least one fit; d) primary filtration of theaqueous suspension of multivesicular liposomal particles by cross-flowfiltration using a filter to exchange the second aqueous phase with anaqueous component to provide an initial volume of aqueous media, whereinthe filter has a membrane pore size from 0.07 to 0.45 μm; e) secondaryfiltration by cross-flow filtration to reduce the initial volume toprovide a subsequent volume of aqueous media that is 10% to 90% of theinitial volume, further wherein the cross-flow filtration is carried outwith a process-scale tangential flow filter with a filtration area of 23square feet or more, wherein all steps are carried out under asepticconditions, f) the composition is prepared in quantities or batchesgreater than a liter; wherein the first emulsion is mixed in a firstemulsification vessel of at least 10 liters in volume; and g) whereinthe uniform size distribution has a number weighted mean particle sizeof at least 10 microns.

In some embodiments provided herein is a method of inducing sensoryblock in a subject, the method comprising injecting into thesubarachnoid space of the subject a composition comprisingmultivesicular liposomes comprising bupivacaine or a salt thereof andhaving a structure including multiple non-concentric chambers andcomprising at least one amphipathic lipid and at least one neutrallipid, wherein said multivesicular liposomes are made by a processcomprising removing organic solvent from multivesicular liposomespre-droplets that comprise a first component core and an aqueous phaseshell with an evaporation apparatus, the evaporation apparatuscomprising: a solvent removal vessel having a top, a bottom and acircular wall; at least one atomizing nozzle; a carrier gas entranceorifice; a solvent removal gas exit orifice centrally connected to thetop; and a product exit orifice connected to the bottom of the vessel,

wherein the process comprises: introducing the pre-droplets to thesolvent removal vessel; applying a carrier gas in a tangential directionto the circular wall through the carrier gas entrance orifice; andremoving a solvent removal gas through the solvent removal gas exitorifice to provide the large diameter synthetic membrane vesicles.

In some embodiments, the sensory block has a longer duration than themotor block induced by injecting into the subarachnoid space of thesubject the same amount of the pharmaceutical composition.

In some embodiments, the sensory block has a longer duration than thesensory block induced by injecting into the subarachnoid space of thesubject non-liposomal bupivacaine containing the same amount ofbupivacaine as the pharmaceutical composition disclosed herein. In someembodiments, injecting into the subarachnoid space of the subject apharmaceutical composition as disclosed herein induces a sensory blockhaving a duration of from about 24 hours to about 72 hours, such as fromabout 24 hours to about 48 hours, such as from about 48 hours to about72 hours. In some embodiments, injecting into the subarachnoid space ofthe subject a pharmaceutical composition described herein reduces painfor a longer period of time than the duration of the motor block inducedby injecting into the subarachnoid space of the subject the same amountof the pharmaceutical composition. Accordingly, in some embodiments ofthe method comprising injecting into the subarachnoid space of thesubject a pharmaceutical composition described herein, wherein ananalgesic, such as an opioid, or such as a non-opioid analgesic, isadministered to the subject, the analgesic is administered after offsetof the motor block.

In some embodiments the at least one polyhydroxy carboxylic acid isselected from the group consisting of glucuronic acid, gluconic acid andtartaric acid.

In some embodiments the amphipathic lipid is selected from the groupconsisting of phosphatidylcholines, phosphatidylethanolamines,sphingomyelins, lysophosphatidylcholines, lysophosphatidylethanolamines,phosphatidylglycerols, phosphatidylserines, phosphatidylinositols,phosphatidic acids, cardiolipins, diacyl dimethylammonium propanes, andstearylamines.

In some embodiments the neutral lipid comprises at least onetriglyceride.

In some embodiments the method comprises administering a therapeuticallyeffective amount of the pharmaceutical composition.

In some embodiments the pharmaceutical composition comprises atherapeutically effective amount of bupivacaine phosphate. In someembodiments the amount of the pharmaceutical composition describedherein is equivalent to from about 100 mg to about 300 mg ofbupivacaine. In some embodiments the amount of the pharmaceuticalcomposition described herein is equivalent to from about 133 mg to about266 mg of bupivacaine. In some embodiments the amount of thepharmaceutical composition described herein is equivalent to from about10 mg to about 70 mg of bupivacaine, such as from about 13.3 mg to about66.5 mg of bupivacaine. In some embodiments the amount of thepharmaceutical composition described herein is equivalent to from about10 mg to about 60 mg of bupivacaine. In some embodiments the amount ofthe pharmaceutical composition described herein is equivalent to fromabout 20 mg to about 60 mg of bupivacaine. In some embodiments theamount of the pharmaceutical composition described herein is equivalentto from about 20 mg to about 50 mg of bupivacaine. In some embodimentsthe amount of the pharmaceutical composition described herein isequivalent to from about 20 mg to about 40 mg of bupivacaine. In someembodiments the amount of the pharmaceutical composition describedherein is equivalent to from about 20 mg to about 30 mg of bupivacaine.In some embodiments the amount of the pharmaceutical compositiondescribed herein is equivalent to from about 30 mg to about 60 mg ofbupivacaine. In some embodiments the amount of the pharmaceuticalcomposition described herein is equivalent to from about 30 mg to about50 mg of bupivacaine. In some embodiments the amount of thepharmaceutical composition described herein is equivalent to from about30 mg to about 40 mg of bupivacaine.

In some embodiments, the pain that may be treated according to themethods disclosed herein is in a region below the diaphragm. In someembodiments, the pain is selected from abdomen pain, lower back pain,hip pain, pelvic pain, femur pain, knee pain, foot pain, and ankle pain.

In some embodiments, the pain is abdomen pain.

In some embodiments, the pain is lower back pain.

In some embodiments, the pain is hip pain.

In some embodiments, the pain is pelvic pain.

In some embodiments, the pain is femur pain.

In some embodiments, the pain is knee pain.

In some embodiments, the pain is foot pain.

In some embodiments, the pain is ankle pain.

In some embodiments the method comprises administering thepharmaceutical composition by epidural injection.

In some embodiments the method does not comprise administering thepharmaceutical composition by epidural injection.

In some embodiments the method comprises administering an analgesic,such as an opioid, to the subject following the injection of thepharmaceutical composition into the subarachnoid space of the subject.

In some embodiments of the methods herein, the opioid is administered ina total amount less than 200 mg, such as less than 100 mg, such as lessthan 50 mg, such as less than 25 mg, such as less than 15 mg, in thefirst about 72 hours following the injection of the pharmaceuticalcomposition into the subarachnoid space of the subject. In someembodiments, the opioid is oxycodone and the method comprisesadministering oxycodone in a total amount less than 15 mg.in the firstabout 72 hours following the injection of the pharmaceutical compositioninto the subarachnoid space of the subject. In some embodiments, themethod comprises administering one or more morphinans to the subject. Insome embodiments, the method comprises administering morphine to thesubject. In some more particular embodiments, the morphine isadministered to the subject for up to 72 hours following the injectionof the pharmaceutical composition into the subarachnoid space of thesubject.

In some embodiments, the method comprises administering one or moreanalgesics to the subject, such as one or more non-opioid analgesics,such as one or more NSAIDs to the subject, following the injection ofthe pharmaceutical composition into the subarachnoid space of thesubject. In some embodiments, the method comprises administering one ormore of ketorolac, acetaminophen or ibuprofen to the subject. In someembodiments, the method comprises administering two or more ofketorolac, acetaminophen or ibuprofen to the subject. In someembodiments, the method comprises administering ketorolac, acetaminophenand ibuprofen to the subject. In some more particular embodiments, theanalgesic, such as the NSAID, such as the one or more of ketorolac,acetaminophen or ibuprofen, is administered to the subject for up to 72hours following the injection of the pharmaceutical composition into thesubarachnoid space of the subject.

In some embodiments, the subject has an AUC for VAS pain intensityscores over the first 72 hours following the injection of thepharmaceutical composition into the subarachnoid space of the subject offrom about 100 to about 200, such as about 125 to 175, such as about 140to 160, such as about 150, such as about 147.9.

In some embodiments of the methods herein, the subject has a pruritusscore as determined by the 5-D itch scale of about 10 to 20, such asabout 12 to 18, such as about 13 to 16, such as about 14 to 15.

In some embodiments of the methods herein, the plasma Cmax ofbupivacaine in the subject is about 150 ng/mL to about 250 ng/mL, suchas about 175 ng/mL to about 225 ng/mL, such as about 200 ng/mL, such asabout 210 mg/mL, for an amount of the pharmaceutical compositiondescribed herein that is equivalent to about 133 mg of bupivacaine. Insome embodiments, the Cmax occurs after about 48 hours following theinjection of the multivesicular liposome composition into thesubarachnoid space of the subject. In some embodiments, the Cmax occursafter about 72 hours following the injection of the multivesicularliposome composition into the subarachnoid space of the subject.

In some embodiments of the methods herein, the plasma Cmax ofbupivacaine in the subject is about 300 ng/mL to about 550 ng/mL, suchas about 350 ng/mL to about 500 ng/mL, such as about 450 mg/mL, such asabout 460 ng/mL, for an amount of the pharmaceutical compositiondescribed herein that is equivalent to about 266 mg of bupivacaine. Insome embodiments, the Cmax occurs after about 48 hours following theinjection of the multivesicular liposome composition into thesubarachnoid space of the subject. In some embodiments, the Cmax occursafter about 72 hours following the injection of the multivesicularliposome composition into the subarachnoid space of the subject.

In some embodiments of the methods herein, the plasma Cmax ofbupivacaine in the subject is less than about 850 ng/mL, such as lessthan about 800 ng/mL, such as less than about 750 ng/mL, such as lessthan about 700 ng/mL, such as less than about 650 ng/mL, such as lessthan about 600 ng/mL.

In some embodiments, the subject is a human.

In some embodiments of the method of treating pain in a subject, whereinthe subject is a first subject, in the first about 72 hours followinginjection of the pharmaceutical composition into the subarachnoid spaceof the first subject the opioid is administered to the first subject ina total amount that is lower than the total amount of an opioid that isadministered to a second subject in the first about 72 hours followinginjection into the subarachnoid space of the second subject ofnon-liposomal bupivacaine containing the same amount of bupivacaine asthe pharmaceutical composition, wherein a pharmaceutical compositioncomprising: a) a multivesicular liposome comprising: at least oneamphipathic lipid, and at least one neutral lipid; and b) an aqueousphase comprising: at least one polyhydroxy carboxylic acid and at leastone di- or tri-protic mineral acid; and bupivacaine phosphate, whereinthe aqueous phase is encapsulated within the multivesicular liposome, isnot administered to the second subject.

In some embodiments of the method of treating pain in a subject, whereinthe subject is a first subject, in the first about 72 hours followinginjection of the pharmaceutical composition into the subarachnoid spaceof the first subject the opioid is administered to the first subject ina total amount that is lower than the total amount of an opioid that isadministered to a second subject in the first about 72 hours followinginjection into the subarachnoid space of the second subject ofnon-liposomal bupivacaine containing the same amount of bupivacaine asthe pharmaceutical composition, wherein a pharmaceutical compositioncomprising: a) a multivesicular liposome comprising: at least oneamphipathic lipid, and at least one neutral lipid; and b) an aqueousphase comprising bupivacaine phosphate, wherein the aqueous phase isencapsulated within the multivesicular liposome, is not administered tothe second subject.

In some embodiments of the method of treating pain in a subject, whereinthe subject is a first subject, in the first about 72 hours followinginjection of the pharmaceutical composition into the subarachnoid spaceof the first subject the opioid is administered to the first subject ina total amount that is lower than the total amount of an opioid that isadministered to a second subject in the first about 72 hours followinginjection into the subarachnoid space of the second subject ofnon-liposomal bupivacaine containing the same amount of bupivacaine asthe pharmaceutical composition, wherein a pharmaceutical compositioncomprising multivesicular liposomes encapsulating bupivacaine phosphate,said multivesicular liposomes comprising:

bupivacaine or a salt thereof;

phosphoric acid;

a lipid component comprising at least one amphipathic lipid and at leastone neutral lipid lacking a hydrophilic head group; and,

optionally, a cholesterol and/or a plant sterol wherein saidmultivesicular liposomes are made by a process comprising:

a) preparing a first aqueous component comprising phosphoric acid;

b) preparing a lipid component comprising at least one organic solvent,at least one amphipathic lipid, and at least one neutral lipid lacking ahydrophilic head group;

c) mixing said first aqueous component and said lipid component to forma water-in-oil emulsion, wherein at least one component comprisesbupivacaine or a salt thereof;

d) mixing said water-in-oil emulsion with a second aqueous component toform solvent spherules; and

e) removing the organic solvent from the solvent spherules to formmultivesicular liposomes encapsulating bupivacaine phosphate,

is not administered to the second subject.

In some embodiments of the method of treating pain in a subject, whereinthe subject is a first subject, in the first about 72 hours followinginjection of the pharmaceutical composition into the subarachnoid spaceof the first subject the opioid is administered to the first subject ina total amount that is lower than the total amount of an opioid that isadministered to a second subject in the first about 72 hours followinginjection into the subarachnoid space of the second subject ofnon-liposomal bupivacaine containing the same amount of bupivacaine asthe pharmaceutical composition, wherein a multivesicular liposomalparticle pharmaceutical composition made by a process comprising: a)providing a volume of first emulsion by mixing a volume of a firstaqueous phase and a volume of a volatile water-immiscible solvent phase,said solvent phase comprising at least one amphipathic lipid and atleast one neutral lipid; b) mixing and emulsifying said first emulsionand a volume of a second aqueous phase in a high shear mixer to providea volume of a second emulsion, said second emulsion comprising acontinuous aqueous phase; and c) removing the volatile water-immisciblesolvent from the second emulsion to form a volume of multivesicularliposomal particle composition, wherein said solvent removal comprisescontacting the second emulsion with an inert gas flow; and wherein saidprocess further comprises primary filtration of the multivesicularliposomal particle composition by cross-flow filtration using a filterhaving a membrane where the multivesicular liposomal particlecomposition does not pass through the membrane; wherein all steps arecarried out under aseptic conditions, and wherein all solutions aresterile filtered, and wherein the multivesicular liposomal particlecomposition is immediately suitable for administration into humans; andwherein the primary filtration comprises: a first concentration of themultivesicular liposomal particle composition; and a buffer exchange,resulting in a pH of the multivesicular liposomal particle compositionof between about 5 and about 8, and the primary filtration is conductedat a transmembrane pressure of from about 0.1 psi to about 20 psi, suchas to about 7 psi,

is not administered to the second subject.

In some embodiments of the method of treating pain in a subject, whereinthe subject is a first subject, in the first about 72 hours followinginjection of the pharmaceutical composition into the subarachnoid spaceof the first subject the opioid is administered to the first subject ina total amount that is lower than the total amount of an opioid that isadministered to a second subject in the first about 72 hours followinginjection into the subarachnoid space of the second subject ofnon-liposomal bupivacaine containing the same amount of bupivacaine asthe pharmaceutical composition, wherein a multivesicular liposomalparticle pharmaceutical composition of pre-determined, uniform sizedistribution, made by a process comprising: a) providing a firstemulsion by mixing a first aqueous phase and a volatile water-immisciblesolvent phase, said solvent phase comprising at least one amphipathiclipid and at least one neutral lipid; b) mixing and emulsifying saidfirst emulsion and a second aqueous phase in a mixer to provide a secondemulsion, said second emulsion comprising a continuous aqueous phase; c)sparging the volatile water-immiscible solvent from the second emulsionto form an aqueous suspension of multivesicular liposomal particles bybubbling an inert gas through the second emulsion using at least onesparge ring, at least one sparge tube or at least one fit; d) primaryfiltration of the aqueous suspension of multivesicular liposomalparticles by cross-flow filtration using a filter to exchange the secondaqueous phase with an aqueous component to provide an initial volume ofaqueous media, wherein the filter has a membrane pore size from 0.07 to0.45 μm; e) secondary filtration by cross-flow filtration to reduce theinitial volume to provide a subsequent volume of aqueous media that is10% to 90% of the initial volume, further wherein the cross-flowfiltration is carried out with a process-scale tangential flow filterwith a filtration area of 23 square feet or more, wherein all steps arecarried out under aseptic conditions, f) the composition is prepared inquantities or batches greater than a liter; wherein the first emulsionis mixed in a first emulsification vessel of at least 10 liters involume; and g) wherein the uniform size distribution has a numberweighted mean particle size of at least 10 microns,

is not administered to the second subject.

In some embodiments of the method of treating pain in a subject, whereinthe subject is a first subject, in the first about 72 hours followinginjection of the pharmaceutical composition into the subarachnoid spaceof the first subject the opioid is administered to the first subject ina total amount that is lower than the total amount of an opioid that isadministered to a second subject in the first about 72 hours followinginjection into the subarachnoid space of the second subject ofnon-liposomal bupivacaine containing the same amount of bupivacaine asthe pharmaceutical composition, wherein a composition comprisingmultivesicular liposomes comprising bupivacaine or a salt thereof andhaving a structure including multiple non-concentric chambers andcomprising at least one amphipathic lipid and at least one neutrallipid, wherein said multivesicular liposomes are made by a processcomprising removing organic solvent from multivesicular liposomespre-droplets that comprise a first component core and an aqueous phaseshell with an evaporation apparatus, the evaporation apparatuscomprising: a solvent removal vessel having a top, a bottom and acircular wall; at least one atomizing nozzle; a carrier gas entranceorifice; a solvent removal gas exit orifice centrally connected to thetop; and a product exit orifice connected to the bottom of the vessel,

wherein the process comprises: introducing the pre-droplets to thesolvent removal vessel; applying a carrier gas in a tangential directionto the circular wall through the carrier gas entrance orifice; andremoving a solvent removal gas through the solvent removal gas exitorifice to provide the large diameter synthetic membrane vesicles,

is not administered to the second subject.

In some embodiments, the opioid that is administered to the firstsubject and the opioid that is administered to the second subject arethe same. In some embodiments, the opioid that is administered to thefirst subject and the opioid that is administered to the second subjectare different.

In some embodiments of the method of treating pain in a subject, whereinthe subject is a first subject, in the first about 72 hours followinginjection of the pharmaceutical composition into the subarachnoid spaceof the first subject, the opioid is administered to the first subject ina total amount that is lower than the total amount of an opioid that isadministered to each of a plurality of second subjects in the firstabout 72 hours following respective injection into the subarachnoidspace of each of the second subjects of non-liposomal bupivacainecontaining the same amount of bupivacaine as the pharmaceuticalcomposition, wherein a pharmaceutical composition comprising: a) amultivesicular liposome comprising: at least one amphipathic lipid, andat least one neutral lipid; and b) an aqueous phase comprising: at leastone polyhydroxy carboxylic acid and at least one di- or tri-proticmineral acid; and bupivacaine phosphate, wherein the aqueous phase isencapsulated within the multivesicular liposome, is not administered tothe second subjects.

In some embodiments of the method of treating pain in a subject, whereinthe subject is a first subject, in the first about 72 hours followinginjection of the pharmaceutical composition into the subarachnoid spaceof the first subject, the opioid is administered to the first subject ina total amount that is lower than the total amount of an opioid that isadministered to each of a plurality of second subjects in the firstabout 72 hours following respective injection into the subarachnoidspace of each of the second subjects of non-liposomal bupivacainecontaining the same amount of bupivacaine as the pharmaceuticalcomposition, wherein a pharmaceutical composition comprising: a) amultivesicular liposome comprising: at least one amphipathic lipid, andat least one neutral lipid; and b) an aqueous phase comprisingbupivacaine phosphate, wherein the aqueous phase is encapsulated withinthe multivesicular liposome,

is not administered to the second subjects.

In some embodiments of the method of treating pain in a subject, whereinthe subject is a first subject, in the first about 72 hours followinginjection of the pharmaceutical composition into the subarachnoid spaceof the first subject, the opioid is administered to the first subject ina total amount that is lower than the total amount of an opioid that isadministered to each of a plurality of second subjects in the firstabout 72 hours following respective injection into the subarachnoidspace of each of the second subjects of non-liposomal bupivacainecontaining the same amount of bupivacaine as the pharmaceuticalcomposition, wherein a pharmaceutical composition comprisingmultivesicular liposomes encapsulating bupivacaine phosphate, saidmultivesicular liposomes comprising:

bupivacaine or a salt thereof;

phosphoric acid;

a lipid component comprising at least one amphipathic lipid and at leastone neutral lipid lacking a hydrophilic head group; and,

optionally, a cholesterol and/or a plant sterol wherein saidmultivesicular liposomes are made by a process comprising:

a) preparing a first aqueous component comprising phosphoric acid;

b) preparing a lipid component comprising at least one organic solvent,at least one amphipathic lipid, and at least one neutral lipid lacking ahydrophilic head group;

c) mixing said first aqueous component and said lipid component to forma water-in-oil emulsion, wherein at least one component comprisesbupivacaine or a salt thereof;

d) mixing said water-in-oil emulsion with a second aqueous component toform solvent spherules; and

e) removing the organic solvent from the solvent spherules to formmultivesicular liposomes encapsulating bupivacaine phosphate,

is not administered to the second subjects.

In some embodiments of the method of treating pain in a subject, whereinthe subject is a first subject, in the first about 72 hours followinginjection of the pharmaceutical composition into the subarachnoid spaceof the first subject, the opioid is administered to the first subject ina total amount that is lower than the total amount of an opioid that isadministered to each of a plurality of second subjects in the firstabout 72 hours following respective injection into the subarachnoidspace of each of the second subjects of non-liposomal bupivacainecontaining the same amount of bupivacaine as the pharmaceuticalcomposition, wherein a multivesicular liposomal particle pharmaceuticalcomposition made by a process comprising: a) providing a volume of firstemulsion by mixing a volume of a first aqueous phase and a volume of avolatile water-immiscible solvent phase, said solvent phase comprisingat least one amphipathic lipid and at least one neutral lipid; b) mixingand emulsifying said first emulsion and a volume of a second aqueousphase in a high shear mixer to provide a volume of a second emulsion,said second emulsion comprising a continuous aqueous phase; and c)removing the volatile water-immiscible solvent from the second emulsionto form a volume of multivesicular liposomal particle composition,wherein said solvent removal comprises contacting the second emulsionwith an inert gas flow; and wherein said process further comprisesprimary filtration of the multivesicular liposomal particle compositionby cross-flow filtration using a filter having a membrane where themultivesicular liposomal particle composition does not pass through themembrane; wherein all steps are carried out under aseptic conditions,and wherein all solutions are sterile filtered, and wherein themultivesicular liposomal particle composition is immediately suitablefor administration into humans; and wherein the primary filtrationcomprises: a first concentration of the multivesicular liposomalparticle composition; and a buffer exchange, resulting in a pH of themultivesicular liposomal particle composition of between about 5 andabout 8, and the primary filtration is conducted at a transmembranepressure of from about 0.1 psi to about 20 psi, such as to about 7 psi,

is not administered to the second subjects.

In some embodiments of the method of treating pain in a subject, whereinthe subject is a first subject, in the first about 72 hours followinginjection of the pharmaceutical composition into the subarachnoid spaceof the first subject, the opioid is administered to the first subject ina total amount that is lower than the total amount of an opioid that isadministered to each of a plurality of second subjects in the firstabout 72 hours following respective injection into the subarachnoidspace of each of the second subjects of non-liposomal bupivacainecontaining the same amount of bupivacaine as the pharmaceuticalcomposition, wherein a multivesicular liposomal particle pharmaceuticalcomposition of pre-determined, uniform size distribution, made by aprocess comprising: a) providing a first emulsion by mixing a firstaqueous phase and a volatile water-immiscible solvent phase, saidsolvent phase comprising at least one amphipathic lipid and at least oneneutral lipid; b) mixing and emulsifying said first emulsion and asecond aqueous phase in a mixer to provide a second emulsion, saidsecond emulsion comprising a continuous aqueous phase; c) sparging thevolatile water-immiscible solvent from the second emulsion to form anaqueous suspension of multivesicular liposomal particles by bubbling aninert gas through the second emulsion using at least one sparge ring, atleast one sparge tube or at least one fit; d) primary filtration of theaqueous suspension of multivesicular liposomal particles by cross-flowfiltration using a filter to exchange the second aqueous phase with anaqueous component to provide an initial volume of aqueous media, whereinthe filter has a membrane pore size from 0.07 to 0.45 μm; e) secondaryfiltration by cross-flow filtration to reduce the initial volume toprovide a subsequent volume of aqueous media that is 10% to 90% of theinitial volume, further wherein the cross-flow filtration is carried outwith a process-scale tangential flow filter with a filtration area of 23square feet or more, wherein all steps are carried out under asepticconditions, f) the composition is prepared in quantities or batchesgreater than a liter; wherein the first emulsion is mixed in a firstemulsification vessel of at least 10 liters in volume; and g) whereinthe uniform size distribution has a number weighted mean particle sizeof at least 10 microns,

is not administered to the second subjects.

In some embodiments of the method of treating pain in a subject, whereinthe subject is a first subject, in the first about 72 hours followinginjection of the pharmaceutical composition into the subarachnoid spaceof the first subject, the opioid is administered to the first subject ina total amount that is lower than the total amount of an opioid that isadministered to each of a plurality of second subjects in the firstabout 72 hours following respective injection into the subarachnoidspace of each of the second subjects of non-liposomal bupivacainecontaining the same amount of bupivacaine as the pharmaceuticalcomposition, wherein a composition comprising multivesicular liposomescomprising bupivacaine or a salt thereof and having a structureincluding multiple non-concentric chambers and comprising at least oneamphipathic lipid and at least one neutral lipid, wherein saidmultivesicular liposomes are made by a process comprising removingorganic solvent from multivesicular liposomes pre-droplets that comprisea first component core and an aqueous phase shell with an evaporationapparatus, the evaporation apparatus comprising: a solvent removalvessel having a top, a bottom and a circular wall; at least oneatomizing nozzle; a carrier gas entrance orifice; a solvent removal gasexit orifice centrally connected to the top; and a product exit orificeconnected to the bottom of the vessel,

wherein the process comprises: introducing the pre-droplets to thesolvent removal vessel; applying a carrier gas in a tangential directionto the circular wall through the carrier gas entrance orifice; andremoving a solvent removal gas through the solvent removal gas exitorifice to provide the large diameter synthetic membrane vesicles,

is not administered to the second subjects.

In some embodiments, the opioid that is administered to the firstsubject and the opioid that is administered to at least one of thesecond subjects are the same. In some embodiments, the opioid that isadministered to the first subject and the opioid that is administered toat least one of the second subjects are different. In some embodiments,the opioid that is administered to the first subject and the opioidsthat are administered to the second subjects are the same. In someembodiments, the opioid that is administered to the first subject andthe opioids that are administered to the second subjects are different.In some embodiments, the total amount of an opioid that is administeredto each of a plurality of second subjects is a mean total amount.

In some embodiments of the methods herein, the opioid is administered tothe first subject in a total amount that is at least about 20% lower,such as at least about 30% lower, such as at least about 40% lower, suchas at least about 50% lower than the total amount of the opioid that isadministered to the second subject. In some embodiments of the methodsherein, the opioid is administered to the first subject in a totalamount that is up to 100% lower (that is, no opioid is administered tothe first subject), such as up to 90% lower, such as up to 80% lower,such as up to 70% lower, such as up to 60% lower, than the total amountof the opioid that is administered to the second subject.

In some embodiments of the methods herein, in the first about 72 hoursfollowing injection of the pharmaceutical composition into thesubarachnoid space of the first subject the opioid is administered tothe first subject in a total amount that is at least about 20% lower,such as at least about 30% lower, such as at least about 40% lower, suchas at least about 50% lower than the total amount of the opioid that isadministered to the second subject in the first about 72 hours followinginjection into the subarachnoid space of the second subject ofnon-liposomal bupivacaine. In some embodiments of the methods herein,the opioid is administered to the first subject in a total amount thatis up to 100% lower (that is, no opioid is administered to the firstsubject), such as up to 90% lower, such as up to 80% lower, such as upto 70% lower, such as up to 60% lower, than the total amount of theopioid that is administered to the second subject.

In some embodiments of the methods herein, in the first about 24 hoursfollowing injection of the pharmaceutical composition into thesubarachnoid space of the first subject the opioid is administered tothe first subject in a total amount that is lower than the total amountof the opioid that is administered to the second subject in the firstabout 24 hours following injection into the subarachnoid space of thesecond subject of non-liposomal bupivacaine. In some embodiments of themethods herein, in the first about 24 hours following injection of thepharmaceutical composition into the subarachnoid space of the firstsubject the opioid is administered to the first subject in a totalamount that is at least about 20% lower, such as at least about 30%lower, such as at least about 40% lower, such as at least about 50%lower than the total amount of the opioid that is administered to thesecond subject in the first about 24 hours injection into thesubarachnoid space of the second subject of non-liposomal bupivacaine.In some embodiments of the methods herein, the opioid is administered tothe first subject in a total amount that is up to 100% lower (that is,no opioid is administered to the first subject), such as up to 90%lower, such as up to 80% lower, such as up to 70% lower, such as up to60% lower, than the total amount of the opioid that is administered tothe second subject.

In some embodiments of the methods herein, in the first about 48 hoursfollowing injection of the pharmaceutical composition into thesubarachnoid space of the first subject the opioid is administered tothe first subject in a total amount that is lower than the total amountof the opioid that is administered to the second subject in the firstabout 48 hours following injection into the subarachnoid space of thesecond subject of non-liposomal bupivacaine. In some embodiments of themethods herein, in the first about 48 hours following injection of thepharmaceutical composition into the subarachnoid space of the firstsubject the opioid is administered to the first subject in a totalamount that is at least about 20% lower, such as at least about 30%lower, such as at least about 40% lower, such as at least about 50%lower than the total amount of the opioid that is administered to thesecond subject in the first about 48 hours following injection into thesubarachnoid space of the second subject of non-liposomal bupivacaine.In some embodiments of the methods herein, the opioid is administered tothe first subject in a total amount that is up to 100% lower (that is,no opioid is administered to the first subject), such as up to 90%lower, such as up to 80% lower, such as up to 70% lower, such as up to60% lower, than the total amount of the opioid that is administered tothe second subject.

In some embodiments of the methods herein, in the first about 7 daysfollowing injection of the pharmaceutical composition into thesubarachnoid space of the first subject the opioid is administered tothe first subject in a total amount that is lower than the total amountof the opioid that is administered to the second subject in the firstabout 7 days following injection into the subarachnoid space of thesecond subject of non-liposomal bupivacaine. In some embodiments of themethods herein, in the first about 7 days following injection of thepharmaceutical composition into the subarachnoid space of the firstsubject the opioid is administered to the first subject in a totalamount that is at least about 20% lower, such as at least about 30%lower, such as at least about 40% lower, such as at least about 50%lower than the total amount of the opioid that is administered to thesecond subject in the first about 7 days following injection into thesubarachnoid space of the second subject of non-liposomal bupivacaine.In some embodiments of the methods herein, the opioid is administered tothe first subject in a total amount that is up to 100% lower (that is,no opioid is administered to the first subject), such as up to 90%lower, such as up to 80% lower, such as up to 70% lower, such as up to60% lower, than the total amount of the opioid that is administered tothe second subject.

In some embodiments of the methods herein, in the first about 14 daysfollowing injection of the pharmaceutical composition into thesubarachnoid space of the first subject the opioid is administered tothe first subject in a total amount that is lower than the total amountof the opioid that is administered to the second subject in the firstabout 14 days following injection into the subarachnoid space of thesecond subject of non-liposomal bupivacaine. In some embodiments of themethods herein, in the first about 14 days following injection of thepharmaceutical composition into the subarachnoid space of the firstsubject the opioid is administered to the first subject in a totalamount that is at least about 20% lower, such as at least about 30%lower, such as at least about 40% lower, such as at least about 50%lower than the total amount of the opioid that is administered to thesecond subject in the first about 14 days following injection into thesubarachnoid space of the second subject of non-liposomal bupivacaine.In some embodiments of the methods herein, the opioid is administered tothe first subject in a total amount that is up to 100% lower (that is,no opioid is administered to the first subject), such as up to 90%lower, such as up to 80% lower, such as up to 70% lower, such as up to60% lower, than the total amount of the opioid that is administered tothe second subject.

In some embodiments of the methods herein, the first subject has an AUCfor VAS pain intensity scores over the first 72 hours followinginjection of the pharmaceutical composition into the subarachnoid spaceof the first subject of from about 100 to about 200, such as about 125to 175, such as about 140 to 160, such as about 150, such as about147.9; and the second subject has an AUC for VAS pain intensity scoresover the first 72 hours following injection into the subarachnoid spaceof the second subject of non-liposomal bupivacaine of from about 150 toabout 250, such as about 165 to 200, such as about 170 to 190, such asabout 175 to 180, such as about 178.5.

In some embodiments of the methods herein, the first subject has an AUCfor VAS pain intensity scores over the first 72 hours followinginjection of the pharmaceutical composition into the subarachnoid spaceof the first subject that is at least about 10% lower, such as at leastabout 17% lower, such as about 27% to about 25% lower, such as at leastabout 25% lower, than the AUC for VAS pain intensity scores for thesecond subject over the first 72 hours following injection into thesubarachnoid space of the second subject of non-liposomal bupivacaine.In some embodiments the first subject has an AUC for VAS pain intensityscores over the first 72 hours following injection of the pharmaceuticalcomposition into the subarachnoid space of the first subject that is upto 100% lower (that is, the AUC is 0), such as up to 90% lower, such asup to 80% lower, such as up to 70% lower, such as up to 60% lower, thanthe AUC for VAS pain intensity scores for the second subject.

In some embodiments of the methods herein, the first subject has apruritus score as determined by the 5-D itch scale that is lower thanthe pruritus score for the second subject.

In some embodiments of the methods herein, the plasma concentration ofbupivacaine in the first subject after about 120 hours followinginjection of the pharmaceutical composition into the subarachnoid spaceof the first subject is at least about 10%, such as least about 20%higher, such as at least about 30% higher, such as at least about 40%higher, such as 50% higher than the plasma concentration of bupivacainein the second subject after about 120 hours following injection into thesubarachnoid space of the second subject of non-liposomal bupivacaine.In some embodiments, the plasma concentration is up to 500% higher, suchas up to 400% higher, such as up to 300% higher, such as up to 200%higher, such as up to 100% higher, than the plasma concentration in thesecond subject.

In some embodiments, the method does not comprise administering ananalgesic, such as an opioid, to the subject following the injection ofthe pharmaceutical composition into the subarachnoid space of thesubject.

In some embodiments, the method does not comprise administering one ormore morphinans to the subject following the injection of thepharmaceutical composition into the subarachnoid space of the subject.In some embodiments, the method does not comprise administering morphineto the subject following the injection of the pharmaceutical compositioninto the subarachnoid space of the subject.

In some embodiments, the method does not comprise administering anopioid to the first subject following the injection of thepharmaceutical composition into the subarachnoid space of the subject.

In some embodiments, the method does not comprise administering one ormore morphinans to the first subject. In some embodiments, the methoddoes not comprise administering morphine to the first subject.

In some embodiments, the first subject is a human and the second subjectis a human. In some embodiments, the method comprises injecting into thesubarachnoid space of the subject an amount of a pharmaceuticalcomposition described herein that is equivalent to about 10 to about 300mg of bupivacaine. In some embodiments the pharmaceutical compositioncomprises an amount equivalent to from about 10 mg to about 300 mg ofbupivacaine. In some embodiments the pharmaceutical compositioncomprises an amount equivalent to from about 133 mg to about 266 mg ofbupivacaine. In some embodiments the pharmaceutical compositioncomprises an amount equivalent to from about 10 mg to about 70 mg ofbupivacaine. In some embodiments the pharmaceutical compositioncomprises an amount equivalent to from about 20 mg to about 60 mg ofbupivacaine. In some embodiments the pharmaceutical compositioncomprises an amount equivalent to from about 20 mg to about 50 mg ofbupivacaine. In some embodiments the pharmaceutical compositioncomprises an amount equivalent to from about 20 mg to about 40 mg ofbupivacaine. In some embodiments the pharmaceutical compositioncomprises an amount equivalent to from about 20 mg to about 30 mg ofbupivacaine. In some embodiments the pharmaceutical compositioncomprises an amount equivalent to from about 30 mg to about 60 mg ofbupivacaine. In some embodiments the pharmaceutical compositioncomprises an amount equivalent to from about 30 mg to about 50 mg ofbupivacaine. In some embodiments the pharmaceutical compositioncomprises an amount equivalent to from about 30 mg to about 40 mg ofbupivacaine. In some embodiments the amount of the pharmaceuticalcomposition described herein is equivalent to from about 10 mg to about70 mg of bupivacaine. In some embodiments the amount of thepharmaceutical composition described herein is equivalent to from about10 mg to about 60 mg of bupivacaine. In some embodiments the amount ofthe pharmaceutical composition described herein is equivalent to fromabout 20 mg to about 60 mg of bupivacaine. In some embodiments theamount of the pharmaceutical composition described herein is equivalentto from about 20 mg to about 50 mg of bupivacaine. In some embodimentsthe amount of the pharmaceutical composition described herein isequivalent to from about 20 mg to about 40 mg of bupivacaine. In someembodiments the amount of the pharmaceutical composition describedherein is equivalent to from about 20 mg to about 30 mg of bupivacaine.In some embodiments the amount of the pharmaceutical compositiondescribed herein is equivalent to from about 30 mg to about 60 mg ofbupivacaine. In some embodiments the amount of the pharmaceuticalcomposition described herein is equivalent to from about 30 mg to about50 mg of bupivacaine. In some embodiments the amount of thepharmaceutical composition described herein is equivalent to from about30 mg to about 40 mg of bupivacaine.

In some embodiments the amount of the pharmaceutical compositiondescribed herein is equivalent to 13.3 mg of bupivacaine. In someembodiments the amount of the pharmaceutical composition describedherein is equivalent to 26.6 mg of bupivacaine. In some embodiments theamount of the pharmaceutical composition described herein is equivalentto 39.9 mg of bupivacaine. In some embodiments the amount of thepharmaceutical composition described herein is equivalent to 53.2 mg ofbupivacaine.

In some embodiments, the method comprises administering one or morenon-opioid analgesics to the subject. In some embodiments, the one ormore non-opioid analgesics are one or more NSAIDs. In some embodiments,the one or more non-opioid analgesics are one or more of ketorolac,acetaminophen or ibuprofen. Thus, in some embodiments, the methodcomprises administering one or more of ketorolac, acetaminophen oribuprofen to the subject, wherein the one or more of ketorolac,acetaminophen or ibuprofen, is administered to the subject for up to 72hours following the injection of the pharmaceutical composition into thesubarachnoid space of the subject in the following amounts:

-   -   IV ketorolac 15 mg once at the time of skin incision closure and        prior to the TAP infiltration    -   Intravenous (IV) acetaminophen 1000 mcg at the time of skin        incision closure    -   Scheduled oral (PO) acetaminophen 650 mg at the end of surgery        and every 6 hours (q6 h) for up to 72 hours    -   Scheduled PO ibuprofen 600 mg at the end of surgery and q6 h for        up to 72 hours

In some embodiments, the method comprises administering an opioid to asubject following the injection of the pharmaceutical composition intothe subarachnoid space of the subject, wherein one or more opioids areadministered in the following amounts:

-   -   oral immediate-release oxycodone at 5-10 mg every 4 hours or as        needed    -   IV morphine at 1-2 mg or hydromorphone initiated at 0.3-0.5 mg        every 4 hours or as needed

In some embodiments, injecting into the subarachnoid space of thesubject the pharmaceutical composition disclosed herein provides aT_(max) of bupivacaine in plasma that is higher than the T_(max) ofbupivacaine in plasma provided by the injection of non-liposomalbupivacaine containing the same amount of bupivacaine as thepharmaceutical composition disclosed herein into the subarachnoid spaceof the subject. In some embodiments T_(max) of bupivacaine in plasmaprovided by the injection of the pharmaceutical composition disclosedherein is about 12 hours to about 36 hours, such as about 24 hours. Insome embodiments T_(max) of non-liposomal bupivacaine in plasma is about20 minutes to about 1 hour, such as about 30 minutes.

In some embodiments, injecting into the subarachnoid space of thesubject the pharmaceutical composition disclosed herein provides aT_(max) of bupivacaine in plasma that is higher than the T_(max) ofbupivacaine in plasma provided by the injection of non-liposomalbupivacaine containing the same amount of bupivacaine as thepharmaceutical composition disclosed herein into the subarachnoid spaceof the subject.

In some embodiments, injecting into the subarachnoid space of thesubject the pharmaceutical composition disclosed herein provides aC_(max) of bupivacaine in plasma that is lower than the C_(max) ofbupivacaine in plasma provided by the injection of non-liposomalbupivacaine containing the same amount of bupivacaine as thepharmaceutical composition disclosed herein into the subarachnoid spaceof the subject.

In some embodiments, injecting into the subarachnoid space of thesubject the pharmaceutical composition disclosed herein provides anapparent terminal elimination half-life (t1/2el) of bupivacaine inplasma that is higher than the t1/2el of bupivacaine in plasma providedby the injection of non-liposomal bupivacaine containing the same amountof bupivacaine as the pharmaceutical composition disclosed herein intothe subarachnoid space of the subject.

In some embodiments, injecting into the subarachnoid space of thesubject the pharmaceutical composition disclosed herein provides anapparent volume of distribution (Vd) of bupivacaine in plasma that islower than the Vd of bupivacaine in plasma provided by the injection ofnon-liposomal bupivacaine containing the same amount of bupivacaine asthe pharmaceutical composition disclosed herein into the subarachnoidspace of the subject.

In some embodiments, injecting into the subarachnoid space of thesubject the pharmaceutical composition induces an onset of motor blockin the subject after a shorter period of time than is provided by theinjection of non-liposomal bupivacaine containing the same amount ofbupivacaine as the pharmaceutical composition disclosed herein into thesubarachnoid space of the subject.

In some embodiments, duration of motor block in the subject is shorterthan duration of motor block in the subject when non-liposomalbupivacaine containing the same amount of bupivacaine as thepharmaceutical composition disclosed herein is administered to thesubarachnoid space of the subject.

In some embodiments, to test onset and duration of motor effects, thefollowing assessments are performed:

-   -   Handheld dynamometer    -   Bromage scale    -   Berg balance scale (7 item)

Thus, in some aspects of embodiments herein, the onset of the motorblock is determined with a handheld dynamometer. In some aspects ofembodiments herein, the onset of the motor block is determined accordingto the Bromage scale. In some aspects of embodiments herein, the onsetof the motor block is determined according to the Berg balance scale.

Thus, in some aspects of embodiments herein, the duration of the motorblock is determined with a handheld dynamometer. In some aspects ofembodiments herein, the duration of the motor block is determinedaccording to the Bromage scale. In some aspects of embodiments herein,the duration of the motor block is determined according to the Bergbalance scale.

In some embodiments, onset and offset of motor block are evaluated usinga handheld dynamometer at knee extension. In some embodiments, onset ofmotor block is defined as the earliest time point after injection intothe subarachnoid space of the subject of the pharmaceutical compositionwhen a 20% or greater weakness from baseline is noted. In someembodiments offset of motor block is defined as the earliest time pointafter onset of motor block when less than 20% weakness from baseline isnoted. Duration of motor block is the time between onset and offset ofmotor block.

In some embodiments, injecting into the subarachnoid space of thesubject the pharmaceutical composition induces an onset of sensory blockin the subject after a longer period of time than is provided by theinjection of non-liposomal bupivacaine containing the same amount ofbupivacaine as the pharmaceutical composition disclosed herein into thesubarachnoid space of the subject.

In some embodiments, duration of sensory block in the subject is longerthan duration of sensory block in the subject when non-liposomalbupivacaine containing the same amount of bupivacaine as thepharmaceutical composition disclosed herein is administered to thesubarachnoid space of the subject.

In some embodiments, onset and segmental spread of sensory block areevaluated by testing the sensitivity to pinprick and cold in the S1, L2,L3, L4, T10-11, T7-8, and T4 dermatomes. In some embodiments, onset ofsensory block is the earliest time point after injection into thesubarachnoid space of the subject of the pharmaceutical composition atwhich loss of sensation is noted below L2, such as S1, L3 and/or L4. Insome embodiments, offset of sensory block will be defined as theearliest time point after onset of block at which recovery of sensationat L4 and S1 is noted.

Duration of sensory block is the time between onset and offset ofsensory block.

Thus, in some aspects of embodiments herein, the onset of the sensoryblock is determined by testing the sensitivity to pinprick in one ormore of the S1, L2, L3, L4, T10-11, T7-8, and T4 dermatomes, such as,for example, the S1, L3 and L4 dermatomes. In some aspects ofembodiments herein, the onset of the sensory block is determined bytesting the sensitivity to cold in one or more of the S1, L2, L3, L4,T10-11, T7-8, and T4 dermatomes, such as, for example, the S1, L3 and L4dermatomes.

Thus, in some aspects of embodiments herein, the offset of the sensoryblock is determined by testing recovery of sensation in one or more ofthe S1, L2, L3, L4, T10-11, T7-8, and T4 dermatomes, such as, forexample, the S1, L3 and L4 dermatomes.

In some embodiments, the injection of the pharmaceutical compositioninto the subarachnoid space of the subject is performed in a manneranalogous to that described in Zel et al., British Journal ofAnaesthesia, 122(3): 1e9 (2018), accepted Oct. 19, 2019, doi:10.1016/j.bja.2018.10.025, incorporated by reference herein in itsentirety.

In some embodiments of any of the methods disclosed herein, the methodproduces postsurgical local analgesia.

In some embodiments of any of the methods disclosed herein, the methodproduces postsurgical regional analgesia.

In some embodiments of any of the methods disclosed herein, the subjectdoes not experience neurological side effects.

In some embodiments of any of the methods disclosed herein, the subjectdoes not experience cardiac side effects.

Unless otherwise defined, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. Although methods and materialssimilar to those described herein can be used in the practice or testingof the present invention, suitable methods and materials are describedbelow. All publications, patent applications, patents, and otherreferences mentioned herein are incorporated by reference in theirentirety. In addition, the materials, methods, and examples areillustrative only and not intended to be limiting.

As used herein, the terms “subarachnoid” and “intrathecal”, for examplein the recitations “subarachnoid injection” and “intrathecal injection”,are used interchangeably. Subarachnoid injection refers to injectionbelow vertebral segment L2.

As used herein, “injecting into the subarachnoid space” a compositionmeans administering the composition by subarachnoid injection.Similarly, “injection into the subarachnoid space” of a compositionmeans administration of the composition by subarachnoid injection.

The term “therapeutically effective” as it pertains to bupivacaine or asalt thereof, such as bupivacaine phosphate, present in thepharmaceutical compositions described herein, means that an anestheticpresent in the first aqueous phase within the multivesicular liposome isreleased in a manner sufficient to achieve a particular level ofanesthesia. Exact dosages will vary depending on such factors as theparticular anesthetic, as well as patient factors such as age, sex,general condition, and the like. Those of skill in the art can readilytake these factors into account and use them to establish effectivetherapeutic concentrations without resort to undue experimentation.

As used herein, “non-liposomal bupivacaine” refers to bupivacaine thatis not in liposomal form. For example, “non-liposomal bupivacaine”refers to bupivacaine that is not comprised in a multivesicularliposome. The term “non-liposomal bupivacaine” also encompasses acomposition comprising bupivacaine that is not in liposomal form.

As used herein, a “VAS pain intensity score” refers to the Visual AnalogScale pain intensity score described in Delgado et al., J Am Acad OrthopSurg Glob Res Rev. 2018 March; 2(3): e088 published online 2018 Mar. 23.doi: 10.5435/JAAOSGlobal-D-17-00088, incorporated by reference herein inits entirety.

In some embodiments the compositions used in the methods disclosedherein comprise a) a multivesicular liposome comprising: at least oneamphipathic lipid, and at least one neutral lipid; and b) an aqueousphase comprising: at least one polyhydroxy carboxylic acid and at leastone di- or tri-protic mineral acid; and bupivacaine phosphate, whereinthe aqueous phase is encapsulated within the multivesicular liposome.

In some embodiments the compositions used in the methods disclosedherein comprise: a) a multivesicular liposome comprising: at least oneamphipathic lipid, and at least one neutral lipid; and b) an aqueousphase comprising bupivacaine phosphate, wherein the aqueous phase isencapsulated within the multivesicular liposome.

In some embodiments the compositions used in the methods disclosedherein comprise multivesicular liposomes encapsulating bupivacainephosphate, said multivesicular liposomes comprising:

bupivacaine or a salt thereof;

phosphoric acid;

a lipid component comprising at least one amphipathic lipid and at leastone neutral lipid lacking a hydrophilic head group; and,

optionally, a cholesterol and/or a plant sterol wherein saidmultivesicular liposomes are made by a process comprising:

a) preparing a first aqueous component comprising phosphoric acid;

b) preparing a lipid component comprising at least one organic solvent,at least one amphipathic lipid, and at least one neutral lipid lacking ahydrophilic head group;

c) mixing said first aqueous component and said lipid component to forma water-in-oil emulsion, wherein at least one component comprisesbupivacaine or a salt thereof;

d) mixing said water-in-oil emulsion with a second aqueous component toform solvent spherules; and

e) removing the organic solvent from the solvent spherules to formmultivesicular liposomes encapsulating bupivacaine phosphate.

In some embodiments the compositions used in the methods disclosedherein are multivesicular liposomal particle pharmaceutical compositionsmade by a process comprising: a) providing a volume of first emulsion bymixing a volume of a first aqueous phase and a volume of a volatilewater-immiscible solvent phase, said solvent phase comprising at leastone amphipathic lipid and at least one neutral lipid; b) mixing andemulsifying said first emulsion and a volume of a second aqueous phasein a high shear mixer to provide a volume of a second emulsion, saidsecond emulsion comprising a continuous aqueous phase; and c) removingthe volatile water-immiscible solvent from the second emulsion to form avolume of multivesicular liposomal particle composition, wherein saidsolvent removal comprises contacting the second emulsion with an inertgas flow; and wherein said process further comprises primary filtrationof the multivesicular liposomal particle composition by cross-flowfiltration using a filter having a membrane where the multivesicularliposomal particle composition does not pass through the membrane;wherein all steps are carried out under aseptic conditions, and whereinall solutions are sterile filtered, and wherein the multivesicularliposomal particle composition is immediately suitable foradministration into humans; and wherein the primary filtrationcomprises: a first concentration of the multivesicular liposomalparticle composition; and a buffer exchange, resulting in a pH of themultivesicular liposomal particle composition of between about 5 andabout 8, and the primary filtration is conducted at a transmembranepressure of from about 0.1 psi to about 20 psi, such as to about 7 psi.

In some embodiments provided herein the compositions used in the methodsdisclosed herein are compositions of pre-determined, uniform sizedistribution, made by a process comprising: a) providing a firstemulsion by mixing a first aqueous phase and a volatile water-immisciblesolvent phase, said solvent phase comprising at least one amphipathiclipid and at least one neutral lipid; b) mixing and emulsifying saidfirst emulsion and a second aqueous phase in a mixer to provide a secondemulsion, said second emulsion comprising a continuous aqueous phase; c)sparging the volatile water-immiscible solvent from the second emulsionto form an aqueous suspension of multivesicular liposomal particles bybubbling an inert gas through the second emulsion using at least onesparge ring, at least one sparge tube or at least one fit; d) primaryfiltration of the aqueous suspension of multivesicular liposomalparticles by cross-flow filtration using a filter to exchange the secondaqueous phase with an aqueous component to provide an initial volume ofaqueous media, wherein the filter has a membrane pore size from 0.07 to0.45 μm; e) secondary filtration by cross-flow filtration to reduce theinitial volume to provide a subsequent volume of aqueous media that is10% to 90% of the initial volume, further wherein the cross-flowfiltration is carried out with a process-scale tangential flow filterwith a filtration area of 23 square feet or more, wherein all steps arecarried out under aseptic conditions, f) the composition is prepared inquantities or batches greater than a liter; wherein the first emulsionis mixed in a first emulsification vessel of at least 10 liters involume; and g) wherein the uniform size distribution has a numberweighted mean particle size of at least 10 microns.

In some embodiments provided herein the compositions used in the methodsdisclosed herein are compositions comprising multivesicular liposomescomprising bupivacaine or a salt thereof and having a structureincluding multiple non-concentric chambers and comprising at least oneamphipathic lipid and at least one neutral lipid, wherein saidmultivesicular liposomes are made by a process comprising removingorganic solvent from multivesicular liposomes pre-droplets that comprisea first component core and an aqueous phase shell with an evaporationapparatus, the evaporation apparatus comprising: a solvent removalvessel having a top, a bottom and a circular wall; at least oneatomizing nozzle; a carrier gas entrance orifice; a solvent removal gasexit orifice centrally connected to the top; and a product exit orificeconnected to the bottom of the vessel,

wherein the process comprises: introducing the pre-droplets to thesolvent removal vessel; applying a carrier gas in a tangential directionto the circular wall through the carrier gas entrance orifice; andremoving a solvent removal gas through the solvent removal gas exitorifice to provide the large diameter synthetic membrane vesicles.

In some embodiments the aqueous phase further comprises hydrochloricacid.

Multivesicular liposomes (or “MVL”, which is used herein to refer to amultivesicular liposome or a plurality of multivesicular liposomes) arelipid vesicles having multiple non-concentric internal aqueous chambershaving internal membranes distributed as a network throughout the MVL.The chambers may contain acids which are effective to enable theencapsulation of bupivacaine or a salt thereof and to modulate itsrelease rate. A preparation of MVL is described, for example, in Kim etal., Biochim. Biophys. Acta 728, 339-348, 1983. In some embodiments, aMVL is prepared in accordance with a process as described in U.S. Pat.No. 9,192,575, incorporated by reference herein in its entirety. In someembodiments, a MVL is prepared in accordance with a process as describedin U.S. Pat. No. 8,182,835, incorporated by reference herein in itsentirety. In some embodiments, a MVL is prepared in accordance with aprocess as described in U.S. Pat. No. 8,834,921, incorporated byreference herein in its entirety. In some embodiments, a MVL is preparedin accordance with a process as described in U.S. Pat. No. 9,205,052,incorporated by reference herein in its entirety.

In some embodiments the multivesicular liposomes (“MVL”) are made by thefollowing process. A “water-in-oil” type emulsion containing anon-hydrohalic acid salt of bupivacaine, such as bupivacaine phosphate,is formed from two immiscible phases, a lipid phase and a first aqueousphase. The lipid phase is made up of at least one amphipathic lipid andat least one neutral lipid in a volatile organic solvent. The term“amphipathic lipid” refers to molecules having a hydrophilic “head”group and a hydrophobic “tail” group and may have membrane-formingcapability. As used herein, amphipathic lipids include those having anet negative charge, a net positive charge, and zwitterionic lipids(having no net charge at their isoelectric point). The term “neutrallipid” refers to oils or fats that have no vesicle-forming capability bythemselves, and lack a charged or hydrophilic “head” group. Examples ofneutral lipids include, but are not limited to, glycerol esters, glycolesters, tocopherol esters, sterol esters which lack a charged orhydrophilic “head” group, and alkanes and squalenes.

The amphipathic lipid is chosen from a wide range of lipids having ahydrophobic region and a hydrophilic region in the same molecule.Suitable amphipathic lipids are zwitterionic phospholipids, includingphosphatidylcholines, phosphatidylethanolamines, sphingomyelins,lysophosphatidylcholines, and lysophosphatidylethanolamines. Alsosuitable are the anionic amphipathic phospholipids such asphosphatidylglycerols, phosphatidylserines, phosphatidylinositols,phosphatidic acids, and cardiolipins. Also suitable are the cationicamphipathic lipids such as acyl trimethylammonium propanes, diacyldimethylammonium propanes, and stearylamines.

Suitable neutral lipids are triglycerides, propylene glycol esters,ethylene glycol esters, and squalene. Examples of triglycerides usefulin the present invention are triolein, tripalmitolein, trimyristolein,trilinolein, tributyrin, tricaproin, tricaprylin, and tricaprin. Thefatty chains in the triglycerides useful in the present invention can beall the same, or not all the same (mixed chain triglycerides), includingall different. Both saturated and unsaturated fatty chains are useful inthe present invention. The propylene glycol esters can be mixed diestersof caprylic and capric acids.

Many types of volatile organic solvents can be used in the presentinvention, including ethers, esters, halogenated ethers, hydrocarbons,halohydrocarbons, or Freons. For example, diethyl ether, chloroform,tetrahydrofuran, ethyl acetate, Forane, and any combinations thereof aresuitable for use in making the compositions of the present invention.

Optionally, other components are included in the lipid phase. Amongthese are cholesterol or plant sterols.

The first aqueous phase includes bupivacaine or a salt thereof, such asbupivacaine phosphate, at least one polyhydroxy carboxylic acid, and atleast one di- or tri-protic mineral acid. In some embodiments, alsoincluded is hydrochloric acid. The di- or tri-protic mineral acidsinclude sulfuric acid, and phosphoric acid. Also included in the firstaqueous phase are such polyhydroxy carboxylic acids as glucuronic acid,gluconic acid, and tartaric acid. The di- and tri-protic mineral acidsand the polyhydroxy organic acids are present in the first aqueous phasein concentrations of from 0.01 mM to about 0.5 M, or preferably fromabout 5 mM to about 300 mM. When hydrochloric acid is used, it ispresent in lower amounts, from about 0.1 mM to about 50 mM, orpreferably from about 0.5 mM to about 25 mM.

The lipid phase and first aqueous phase are mixed by mechanicalturbulence, such as through use of rotating or vibrating blades,shaking, extrusion through baffled structures or porous pipes, byultrasound, or by nozzle atomization, to produce a water-in-oilemulsion. Thus, bupivacaine or a salt thereof, such as bupivacainephosphate, is encapsulated directly in the first step of MVLmanufacture.

The whole water-in-oil emulsion is then dispersed into a second aqueousphase by means described above, to form solvent spherules suspended inthe second aqueous phase. The term “solvent spherules” refers to amicroscopic spheroid droplet of organic solvent, within which aresuspended multiple smaller droplets of aqueous solution. The resultingsolvent spherules therefore contain multiple aqueous droplets with thebupivacaine or a salt thereof, such as bupivacaine phosphate, dissolvedtherein. The second aqueous phase can contain additional components suchas glucose, and/or lysine.

The volatile organic solvent is then removed from the spherules, forinstance by surface evaporation from the suspension: When the solvent issubstantially or completely evaporated, MVL are formed. Gases which canbe used for the evaporation include nitrogen, argon, helium, oxygen,hydrogen, and carbon dioxide. Alternatively, the volatile solvent can beremoved by sparging, rotary evaporation, or with the use of solventselective membranes.

In some embodiments, an MVL is prepared in accordance with a process asdescribed in U.S. Pat. No. 10,398,648, incorporated by reference hereinin its entirety. In some embodiments, a MVL is prepared in accordancewith a process as described in U.S. Pat. No. 9,585,838 incorporated byreference herein in its entirety.

In some embodiments, a MVL is prepared in accordance with a process asdescribed in US 2011-0250264, US 2013-0306759, US 2013-0177634, US2013-0177633, US 2013-0177635, US 2013-0195965, US 2013-0177636, US2013-0183373, US 2013-0177638, US 2013-0177637, US 2013-0183372, US2013-0183375, US 2016-0361260 or US 2018-0092847, each of which isincorporated by reference herein in its entirety.

Examples Example 1—Clinical Trial

On Day 1, eligible subjects will be randomized in blocks of 5, in aratio of 3:1:1 to receive EXPAREL® or bupivacaine or placebo (saline)injection, respectively. EXPAREL® is the trade name for thepharmaceutical composition disclosed herein. Starting with treatmentcohort 1, healthy volunteers will be randomized to the 3 treatment armswithin cohorts. Each cohort will consist of 10 subjects (6 EXPAREL®, 2bupivacaine and 2 placebo).

In each cohort, within the EXPAREL® arm, subjects will be randomized 2:1with 4 subjects undergoing cerebrospinal fluid (CSF) tap and 2 subjectsnot undergoing CSF tap. Subjects who are not undergoing CSF tap, willundergo a CSF sham draw to prevent subject bias. This will allow for thefull characterization of the pharmacodynamic profile of the drug inthese subjects without risk of drug removal from the CSF.

For those subjects randomized to the EXPAREL® arm—the dose of MVL willbe determined by the cohort. Starting at 1 mL (13.3 mg) for cohort 1,the volume of EXPAREL® will be increased by 1 mL in each subsequentcohort for a maximum of 4 mL (53.2 mg), as described in the table below.

In each cohort, subjects randomized to the bupivacaine arm will receive15 mg of plain bupivacaine HCL (the equivalent of 13.3 mg bupivacainebase) providing a 1:1 reference to the starting dose level chosen forEXPAREL®.

The decision to proceed to the next cohort will be made following a fullreview of the safety, PK, and PD (sensory and motor) data from theprevious completed cohort(s).

The following summarizes the treatment for each cohort:

EXPAREL® Arm:

For those subjects randomized to EXPAREL® arm, the dose of EXPAREL® willbe determined by the cohort. Starting at 1 mL (13.3 mg) for cohort 1,the volume of EXPAREL® will be increased by 1 mL in each subsequentcohort for a maximum of 4 mL (53.2 mg), as described in the table below.

Volume (mL) of Dose (mg) of Treatment Cohorts EXPAREL ® bupivacaine 1 113.3 2 2 26.6 3 3 39.9 4 4 53.2

Bupivacaine Arm:

In each cohort, subjects randomized to the bupivacaine arm will receive15 mg of plain bupivacaine HCL (the equivalent of 13.3 mg bupivacainebase) providing a 1:1 reference to the starting dose level chosen forEXPAREL®.

Placebo Arm:

Subjects in the placebo arm will receive normal saline intrathecalinjection.

Intrathecal Injection (in General):

Subject will be placed in the sitting position. After prepping thelumbar area, the drug will be injected in the lumbar intrathecal spacevia a single shot intrathecal injection at the L3 and L4 level. Thesubjects will be placed in supine position after completion of spinalinjection.

The administration of the study drug and CSF tap will be limited toselected study team members. These members will be unblinded to thetreatment arm as EXPAREL® is visibly different from bupivacaine orsaline.

Test Product, Dose, Mode of Administration, and Lot Number:

-   -   Name: EXPAREL® (bupivacaine liposome injectable suspension)        Active Ingredient: Bupivacaine, 13.3 mg/mL    -   Dosage: Single injection of EXPAREL®    -   Lot Number: To Be Determined    -   Mode of Administration: Injection into the Intrathecal space.

Reference Product, Dose, Mode of Administration, and Lot Numbers:

-   -   Name: Bupivacaine HCl    -   Active Ingredient: Bupivacaine    -   Dosage: Single injection into the Intrathecal space.    -   Mode of Administration: Injection into the Intrathecal space

Reference Product, Dose, Mode of Administration, and Lot Numbers:

-   -   Name: Placebo    -   Active Ingredient: Normal Saline (1 ml)    -   Dosage: Single injection into the Intrathecal space.    -   Mode of Administration: Injection into the Intrathecal space.

Pharmacokinetic Assessments:

Venous blood samples will be obtained from subjects in all cohorts andtreatment arms and will be collected on Day 1 predose (up to 30 minsbefore drug administration), and 5 min (±5 min), 1(±1 hr), 3(±1 hr),6(±1 hr), 12(±1 hr), 15(±1 hr), 20(±1 hr), 24(±1 hr), 30(±4 hr), 42(±4hr), 96(±4 hr) and 144(±4 hr) hours from the end of study drugadministration.

In addition, CSF samples will be obtained from all subjects except theno CSF tap (or no tap) group of EXPAREL® arm at the following times—

-   -   Day 1 predose (up to 5 mins prior to injection of study drug)    -   24 hours (±6 hours), in the absence of motor block    -   48 hours (±6 hours), in the absence of motor block    -   96 hours (±6 hours), in the absence of motor block

In the presence of motor block at any of the above scheduled timepoints, the sampling time point will be delayed until the offset of themotor block is noted. The subsequent CSF sampling time point would thenoccur 24 hours later.

The subjects from the no CSF tap (or no tap) group of EXPAREL® arm, willserve as controls providing an accurate assessment of the PD effects ofEXPAREL® without risk of drug removal during the CSF tap.

Start of drug administration is defined as the time of intrathecalneedle insertion. End of drug administration is defined as the time ofneedle removal.

Pharmacokinetic Endpoints:

The following model-predicted PK endpoints will be determined:

-   -   Area under the plasma concentration-versus-time curve (AUC0-last        and AUC0-∞).    -   Maximum plasma concentration (C_(max)) and time of C_(max)        (T_(max)).    -   The apparent terminal elimination half-life (t1/2e1).    -   Apparent clearance (CL/F).    -   Apparent volume of distribution (Vd).

Pharmacodynamic Assessment:

Sensory Assessment:

Onset and segmental spread of sensory block will be evaluated by testingthe sensitivity to pinprick and cold in the S1, L2, L3, L4, T10-11,T7-8, and T4 dermatomes

Onset of sensory block will be defined as the earliest time point afterdrug administration at which loss of sensation is noted below L2, suchas S1, L3 and L4. Offset of sensory block will be defined as theearliest time point after onset of block at which recovery of sensationat L4 and S1 is noted. Duration of sensory block will be defined as thetime between onset and offset of sensory block.

Motor Assessment:

To test onset and duration of motor effects, the following assessmentswill be performed:

-   -   Handheld dynamometer    -   Bromage scale    -   Berg balance scale (7 item)

Onset and offset of motor block will be defined using the handhelddynamometer at knee extension. Onset of motor block will be defined asthe earliest time point after drug administration when a 20% or greaterweakness from baseline is noted. Offset of motor block will be definedas the earliest time point after onset of motor block when less than 20%weakness from baseline is noted. Duration of motor block will be definedas the time between onset and offset of motor block.

-   -   Handheld dynamometer

The handheld dynamometer is a reliable and validated method of motorfunction assessment (Mentiplay 2015). A MicroFET2 handheld dynamometer(Hoggan Health Industries) will be used to test motor function. Thedynamometer will be used to test hip flexion, knee extension, and ankledorsiflexion. For hip and knee tests, the subject will be placed insitting position with the hips and knees flexed at 90°. For the hipflexion test, the dynamometer is placed close to the knee joint, on theanterior part of the thigh. For the knee extension test, the dynamometerwill be placed close to the ankle joint, on the anterior aspect of theleg. For ankle dorsiflexion test, the subject will be in the supineposition with hips and knees extended, and ankles relaxed. Thedynamometer will be placed over the metatarsal heads on the dorsum ofthe foot.

-   -   Bromage scale

Bromage scale will be used to characterize the motor block (Bromage1965)

Score Intensity of motor block I Unable to move feet or knees II Able tomove feet only III Just able to move knees IV Full flexion of knees andfeet

-   -   Berg balance scale (7 item)

The 7-item Berg balance scale will be used for this study (Chou 2006).

Item description Sitting to standing Able to stand without using handand stabilize independently 2 Able to stand using hands after severalties 1 Needs moderate or maximal assistance to stand 0 Standingunsupported with eyes closed Able to stand for 10 seconds safely 2 Ableto stand for 3 seconds 1 Needs help to keep from falling 0 Reachingforward with outstretched arm while standing Can reach forwardconfidently >25 cm (10″) 2 Can reach forward safely >5 cm (2″) 1 Losesbalance while trying/requires external support 0 Pick up object fromfloor from a standing position Able to pick up slipper safely and easily2 no pick up but 2-5 cm(1-2″) from slipper keeping balance 1independently Unable to try/needs assistance to keep from losing balanceor 0 falling Turning to look behind over left and right shoulders whilestanding Looks behind from both sides and weight shifts well 2 Turnssideways only but maintains balance 1 Needs assistance to keep fromlosing or falling 0 Standing unsupported one foot in front Able to placefoot in tandem independently and hold for 30 2 seconds Able to takesmall step independently and hold for 30 seconds 1 Loses balance whilestepping or standing 0 Indicate which foot is in front Left RightStanding on one leg Able to lift leg independently and hold for >10seconds 2 Able to lift leg independently and hold for = or >3 seconds 1Unable to try/needs assistance to prevent fall 0 Indicate which foot isin front Left Right

Pharmacodynamic Endpoints:

-   -   Average time to onset of the sensory and motor block    -   Average duration of the sensory and motor block

Safety Assessment:

AEs and SAES will be monitored and recorded from the time the ICF issigned through Day 30. All AEs and SAES should be reported by the studystaff within 24 hours of occurrence of the event.

In the event of an AE or SAE, the following safety measurements will beperformed and recorded:

-   -   Sensory test (pinprick and cold test)    -   Motor test (handheld dynamometer, Bromage scale and Berg balance        scale (7 item)), if possible    -   3-lead ECG    -   Neurological history questionnaire    -   Vital signs (HR, BP, cardiac output, RR, CO2 and O2 saturation)    -   Additional blood and/or CSF samples may be obtained, at the        discretion of the investigator.    -   Phone call Day 30 (±3 days)

Neurological History Questionnaire:

Responses to the following questions will be recorded at screening, Day1 (pre-dose—up to 3 hr prior to drug administration), at each sensoryand motor assessment (Day 1-5), at discharge (Day 6), follow up visit(Day 9), Day 30 (±3 days) phone call and in the event of an AE.

-   -   Do you have any back pain? If yes, where? Describe the quality        and severity. Does it radiate into your legs? If so, where?    -   Do you have any feeling of weakness in your legs? If so, where?    -   Do you have any numbness/tingling in your legs? If so, where?    -   Do you have any numbness/strange sensations in your buttock or        perineal area?    -   Have you had any issues with bowel or bladder incontinence?

Safety Endpoints:

The following safety endpoints will be assessed based on the safetyassessments throughout the study

-   -   Incidence of treatment-emergent AEs (TEAEs) through Day 9.    -   Proportion of subjects who have any of the neurological events.

List of Acronyms/Abbreviations AE Adverse event ALT Alanineaminotransferase ASA American Society of Anesthesiologists AST Aspartateaminotransferase AUC Area under the curve BP Blood pressure CFR Code ofFederal Regulations CL/F Apparent clearance C_(max) The maximum observedplasma concentration obtained directly from the experimental datawithout interpolation CO₂ Carbon dioxide CRF Case Report Form CSFCerebrospinal fluid DEC Dose escalation committee ECG ElectrocardiogramEDTA Ethylenediaminetetraacetic acid EPRU Early Phase Research Unit FDAFood and Drug Administration FSH Follicle stimulating hormone GCP GoodClinical Practice HIV Human immunodeficiency virus HR Heart rate ICFInformed consent form ICH International Conference on Harmonisation INDInvestigational New Drug IRB Institutional Review Board IV IntravenousMedDRA Medical Dictionary for Regulatory Activities NDA New DrugApplication NSAIDs Non-steroidal anti-inflammatory drugs O₂ Oxygen PDPharmacodynamic PICC Peripherally inserted central catheter PKPharmacokinetic PO Oral PTAE Pretreatment adverse event RR Respiratoryrate SAE Serious adverse event SAP Statistical analysis plan sNDASupplemental New Drug Application SOC Standard of care t_(1/2el) Theapparent terminal elimination half-life TEAE Treatment-emergent adverseevent T_(max) The time to maximum plasma concentration ULN Upper limitof normal US United States (of America) Vd Apparent volume ofdistribution WOCBP Women of childbearing potential

1. A method of treating pain in a subject, the method comprisinginjecting into the subarachnoid space of the subject a pharmaceuticalcomposition comprising: a) a multivesicular liposome comprising: atleast one amphipathic lipid, and at least one neutral lipid; and b) anaqueous phase comprising bupivacaine phosphate, wherein the aqueousphase is encapsulated within the multivesicular liposome.
 2. A method oftreating pain in a subject, the method comprising injecting into thesubarachnoid space of the subject a pharmaceutical compositioncomprising multivesicular liposomes encapsulating bupivacaine phosphate,said multivesicular liposomes comprising: bupivacaine or a salt thereof;phosphoric acid; a lipid component comprising at least one amphipathiclipid and at least one neutral lipid lacking a hydrophilic head group;and, optionally, a cholesterol and/or a plant sterol wherein saidmultivesicular liposomes are made by a process comprising: a) preparinga first aqueous component comprising phosphoric acid; b) preparing alipid component comprising at least one organic solvent, at least oneamphipathic lipid, and at least one neutral lipid lacking a hydrophilichead group; c) mixing said first aqueous component and said lipidcomponent to form a water-in-oil emulsion, wherein at least onecomponent comprises bupivacaine or a salt thereof; d) mixing saidwater-in-oil emulsion with a second aqueous component to form solventspherules; and e) removing the organic solvent from the solventspherules to form multivesicular liposomes encapsulating bupivacainephosphate.
 3. The method of claim 1 or 2, wherein the aqueous phasefurther comprises hydrochloric acid.
 4. The method of any one of claims1 to 3, wherein the amphipathic lipid is selected from the groupconsisting of phosphatidylcholines, phosphatidylethanolamines,sphingomyelins, lysophosphatidylcholines, lysophosphatidylethanolamines,phosphatidylglycerols, phosphatidylserines, phosphatidylinositols,phosphatidic acids, cardiolipins, diacyl dimethylammonium propanes, andstearylamines.
 5. The method of any one of claims 1 to 4, wherein theneutral lipid is at least one triglyceride.
 6. The method of any one ofclaims 1 to 5, wherein the pharmaceutical composition comprises atherapeutically effective amount of bupivacaine phosphate.
 7. The methodof claim any one of the preceding claims, wherein the pharmaceuticalcomposition comprises from about 10 mg to about 60 mg of bupivacainephosphate.
 8. The method of claim 7, wherein the pharmaceuticalcomposition comprises from about 20 mg to about 60 mg of bupivacainephosphate.
 9. The method of claim 7, wherein the pharmaceuticalcomposition comprises from about 30 mg to about 60 mg of bupivacainephosphate.
 10. The method of any one of the preceding claims, whereinthe method comprises administering the pharmaceutical composition byepidural injection.
 11. The method of any one of the preceding claims,wherein the method does not comprise administering the pharmaceuticalcomposition by epidural injection.
 12. The method of claim 1, whereinthe pain is in a region below the diaphragm.
 13. The method of claim 12,wherein the pain is selected from abdomen pain, lower back pain, hippain, pelvic pain, femur pain, knee pain, foot pain, and ankle pain. 14.The method of any one of the preceding claims, wherein the method doesnot comprise administering an opioid to the subject following theinjection of the pharmaceutical composition into the subarachnoid spaceof the subject.
 15. The method of any one of the preceding claims,wherein the method comprises administering an opioid to the subjectfollowing the injection of the pharmaceutical composition into thesubarachnoid space of the subject.
 16. The method of claim 15, whereinthe opioid is oxycodone and the method comprises administering oxycodonein a total amount less than 15 mg in the first about 72 hours followingthe injection of the pharmaceutical composition into the subarachnoidspace of the subject.
 17. The method of any one of claims 11 to 16,wherein the method comprises administering a non-opioid analgesic to thesubject following the injection of the pharmaceutical composition intothe subarachnoid space of the subject.
 18. The method of claim any oneof claims 15 to 17, wherein the subject is a first subject, wherein inthe first about 72 hours following the injection of the pharmaceuticalcomposition into the subarachnoid space of the first subject the opioidis administered to the first subject in a total amount that is lowerthan the total amount of an opioid that is administered to a secondsubject in the first about 72 hours following injection into thesubarachnoid space of the second subject of non-liposomal bupivacainecontaining the same amount of bupivacaine as the pharmaceuticalcomposition, wherein a pharmaceutical composition comprising: a) amultivesicular liposome comprising: at least one amphipathic lipid, andat least one neutral lipid; and b) an aqueous phase comprisingbupivacaine phosphate, wherein the aqueous phase is encapsulated withinthe multivesicular liposome, is not administered to the second subject.19. The method of claim any one of claims 15 to 17, wherein the subjectis a first subject, wherein in the first about 72 hours following theinjection of the pharmaceutical composition into the subarachnoid spaceof the first subject the opioid is administered to the first subject ina total amount that is lower than the total amount of an opioid that isadministered to a second subject in the first about 72 hours followinginjection into the subarachnoid space of the second subject ofnon-liposomal bupivacaine containing the same amount of bupivacaine asthe pharmaceutical composition, wherein a pharmaceutical compositioncomprising multivesicular liposomes encapsulating bupivacaine phosphate,said multivesicular liposomes comprising: bupivacaine or a salt thereof;phosphoric acid; a lipid component comprising at least one amphipathiclipid and at least one neutral lipid lacking a hydrophilic head group;and, optionally, a cholesterol and/or a plant sterol wherein saidmultivesicular liposomes are made by a process comprising: a) preparinga first aqueous component comprising phosphoric acid; b) preparing alipid component comprising at least one organic solvent, at least oneamphipathic lipid, and at least one neutral lipid lacking a hydrophilichead group; c) mixing said first aqueous component and said lipidcomponent to form a water-in-oil emulsion, wherein at least onecomponent comprises bupivacaine or a salt thereof; d) mixing saidwater-in-oil emulsion with a second aqueous component to form solventspherules; and e) removing the organic solvent from the solventspherules to form multivesicular liposomes encapsulating bupivacainephosphate, , is not administered to the second subject.
 20. The methodof claim 18 or 19, wherein non-liposomal bupivacaine or a salt thereofis administered to the second subject following injection into thesubarachnoid space of the second subject of non-liposomal bupivacainecontaining the same amount of bupivacaine as the pharmaceuticalcomposition.
 21. The method of claim 20, wherein non-liposomalbupivacaine hydrochloride is administered to the second subjectfollowing injection into the subarachnoid space of the second subject ofnon-liposomal bupivacaine containing the same amount of bupivacaine asthe pharmaceutical composition.
 22. The method of claim 18, 19, 20 or21, wherein the opioid is administered to the first subject in a totalamount that is about 20% lower, such as at least about 30% lower, suchas at least about 40% lower, such as at least about 50% lower than thetotal amount of the opioid that is administered to the second subject.23. The method of claim 18, 19, 20, 21 or 22, wherein in the first about24 hours following the injection of the pharmaceutical composition intothe subarachnoid space of the first subject the opioid is administeredto the first subject in a total amount that is lower than the totalamount of the opioid that is administered to the second subject in thefirst about 24 hours following injection into the subarachnoid space ofthe second subject of non-liposomal bupivacaine containing the sameamount of bupivacaine as the pharmaceutical composition.
 24. The methodof any one of claims 18 to 23, wherein in the first about 48 hoursfollowing the injection of the pharmaceutical composition into thesubarachnoid space of the first subject the opioid is administered tothe first subject in a total amount that is lower than the total amountof the opioid that is administered to the second subject in the firstabout 48 hours following injection into the subarachnoid space of thesecond subject of non-liposomal bupivacaine containing the same amountof bupivacaine as the pharmaceutical composition.
 25. The method of anyone of claims 18 to 24, wherein in the first about 7 days following theinjection of the pharmaceutical composition into the subarachnoid spaceof the first subject the opioid is administered to the first subject ina total amount that is lower than the total amount of the opioid that isadministered to the second subject in the first about 7 days followinginjection into the subarachnoid space of the second subject ofnon-liposomal bupivacaine containing the same amount of bupivacaine asthe pharmaceutical composition.
 26. The method of any one of claims 18to 25, wherein in the first about 14 days following the injection of thepharmaceutical composition into the subarachnoid space of the firstsubject the opioid is administered to the first subject in a totalamount that is lower than the total amount of the opioid that isadministered to the second subject in the first about 14 days hoursfollowing injection into the subarachnoid space of the second subject ofnon-liposomal bupivacaine containing the same amount of bupivacaine asthe pharmaceutical composition.
 27. The method of claim 23, wherein theopioid is administered to the first subject in a total amount in thefirst about 24 hours the injection of the pharmaceutical compositioninto the subarachnoid space of the first subject that is at least about20% lower, such as at least about 30% lower, such as at least about 40%lower, such as at least about 50% lower than the total amount of theopioid that is administered to the second subject in the first about 24hours following injection into the subarachnoid space of the secondsubject of non-liposomal bupivacaine containing the same amount ofbupivacaine as the pharmaceutical composition.
 28. The method of claim24, wherein the opioid is administered to the first subject in a totalamount in the first about 48 hours following the injection of thepharmaceutical composition into the subarachnoid space of the firstsubject that is at least about 20% lower, such as at least about 30%lower, such as at least about 40% lower, such as at least about 50%lower than the total amount of the opioid that is administered to thesecond subject in the first about 48 hours following injection into thesubarachnoid space of the second subject of non-liposomal bupivacainecontaining the same amount of bupivacaine as the pharmaceuticalcomposition
 29. The method of claim 25, wherein the opioid isadministered to the first subject in a total amount in the first about 7days hours following the injection of the pharmaceutical compositioninto the subarachnoid space of the first subject that is at least about20% lower, such as at least about 30% lower, such as at least about 40%lower, such as about 50% lower than the total amount of the opioid thatis administered to the second subject in the first about 7 daysfollowing injection into the subarachnoid space of the second subject ofnon-liposomal bupivacaine containing the same amount of bupivacaine asthe pharmaceutical composition.
 30. The method of claim 26, wherein theopioid is administered to the first subject in a total amount in thefirst about 14 days following the injection of the pharmaceuticalcomposition into the subarachnoid space of the first subject that is atleast about 20% lower, such as at least about 30% lower, such as about40% lower than the total amount of the opioid that is administered tothe second subject in the first about 14 days following injection intothe subarachnoid space of the second subject of non-liposomalbupivacaine containing the same amount of bupivacaine as thepharmaceutical composition.
 31. The method of any one of claims 1 to 17,wherein the subject has an AUC for VAS pain intensity scores over thefirst 72 hours following the injection of the pharmaceutical compositioninto the subarachnoid space of the subject of from about 100 to about200, such as about 125 to 175, such as about 140 to 160, such as about150, such as about 147.9.
 32. The method of any one of claims 18 to 30,wherein the first subject has an AUC for VAS pain intensity scores overthe first 72 hours following the injection of the pharmaceuticalcomposition into the subarachnoid space of the first subject of fromabout 100 to about 200, such as about 125 to 175, such as about 140 to160, such as about 150, such as about 147.9; and the second subject hasan AUC for VAS pain intensity scores over the first 72 hours followinginjection into the subarachnoid space of the second subject ofnon-liposomal bupivacaine containing the same amount of bupivacaine asthe pharmaceutical composition of from about 150 to about 250, such asabout 165 to 200, such as about 170 to 190, such as about 175 to 180,such as about 178.5.
 33. The method of any one of claims 18 to 30,wherein the first subject has an AUC for VAS pain intensity scores overthe first 72 hours following the injection of the pharmaceuticalcomposition into the subarachnoid space of the first subject that is atleast about 10% lower, such as at least about 17% lower, such as about27% to about 25% lower, such as at least about 25% lower, than the AUCfor VAS pain intensity scores for the second subject over the first 72hours following injection into the subarachnoid space of the secondsubject of non-liposomal bupivacaine containing the same amount ofbupivacaine as the pharmaceutical composition.
 34. The method of any oneof claim 1 to 18 or 31, wherein the subject has a pruritus score asdetermined by the 5-D itch scale of about 10 to about
 20. 35. The methodof any one of claims 18 to 30 or 32 to 33, wherein the first subject hasa pruritus score as determined by the 5-D itch scale that is lower thanthe pruritus score for the second subject.
 36. The method of any one ofclaim 1 to 18, 31, or 34, wherein the plasma concentration ofbupivacaine in the subject after about 120 hours following the injectionof the pharmaceutical composition into the subarachnoid space of thesubject is about is about 150 ng/mL to about 250 ng/mL, such as about175 ng/mL to about 225 ng/mL, such as about 200 ng/mL, such as about 210mg/mL, for an amount of the pharmaceutical composition described hereinthat is equivalent to about 133 mg of bupivacaine.
 37. The method of anyone of claim 18 to 30, 32 to 33, or 35, wherein the plasma concentrationof bupivacaine in the first subject after about 120 hours following theinjection of the pharmaceutical composition into the subarachnoid spaceof the first subject is at least about 10%, such as least about 20%higher, such as at least about 30% higher, such as at least about 40%higher, such as 50% higher than the plasma concentration of bupivacainein the second subject after about 120 hours following injection into thesubarachnoid space of the second subject of non-liposomal bupivacainecontaining the same amount of bupivacaine as the pharmaceuticalcomposition.
 38. The method of any one of the preceding claims, whereinthe method does not comprise administering an opioid to the subjectfollowing the injection of the pharmaceutical composition into thesubarachnoid space of the first subject.
 39. The method of claim any oneof claims 14 to 17, wherein the subject is a first subject, wherein inthe first about 72 hours following the injection of the pharmaceuticalcomposition into the subarachnoid space of the first subject the opioidis administered to the first subject in a total amount that is lowerthan the total amount of an opioid that is administered to each of aplurality of second subjects in the first about 72 hours followingrespective injection into the subarachnoid space of each of the secondsubjects of non-liposomal bupivacaine containing the same amount ofbupivacaine as the pharmaceutical composition, wherein a pharmaceuticalcomposition comprising: a) a multivesicular liposome comprising: atleast one amphipathic lipid, and at least one neutral lipid; and b) anaqueous phase comprising bupivacaine phosphate, wherein the aqueousphase is encapsulated within the multivesicular liposome, is notadministered to the second subjects.
 40. The method of claim any one ofclaims 14 to 17, wherein the subject is a first subject, wherein in thefirst about 72 hours following the injection of the pharmaceuticalcomposition into the subarachnoid space of the first subject the opioidis administered to the first subject in a total amount that is lowerthan the total amount of an opioid that is administered to each of aplurality of second subjects in the first about 72 hours followingrespective injection into the subarachnoid space of each of the secondsubjects of non-liposomal bupivacaine containing the same amount ofbupivacaine as the pharmaceutical composition, wherein a pharmaceuticalcomposition comprising multivesicular liposomes encapsulatingbupivacaine phosphate, said multivesicular liposomes comprising:bupivacaine or a salt thereof; phosphoric acid; a lipid componentcomprising at least one amphipathic lipid and at least one neutral lipidlacking a hydrophilic head group; and, optionally, a cholesterol and/ora plant sterol wherein said multivesicular liposomes are made by aprocess comprising: a) preparing a first aqueous component comprisingphosphoric acid; b) preparing a lipid component comprising at least oneorganic solvent, at least one amphipathic lipid, and at least oneneutral lipid lacking a hydrophilic head group; c) mixing said firstaqueous component and said lipid component to form a water-in-oilemulsion, wherein at least one component comprises bupivacaine or a saltthereof; d) mixing said water-in-oil emulsion with a second aqueouscomponent to form solvent spherules; and e) removing the organic solventfrom the solvent spherules to form multivesicular liposomesencapsulating bupivacaine phosphate, is not administered to the secondsubjects.
 41. A method of inducing motor block in a subject, the methodcomprising injecting into the subarachnoid space of the subject apharmaceutical composition comprising: a) a multivesicular liposomecomprising: at least one amphipathic lipid, and at least one neutrallipid; and b) an aqueous phase comprising bupivacaine phosphate, whereinthe aqueous phase is encapsulated within the multivesicular liposome.42. A method of inducing motor block in a subject, the method comprisinginjecting into the subarachnoid space of the subject a pharmaceuticalcomposition comprising multivesicular liposomes encapsulatingbupivacaine phosphate, said multivesicular liposomes comprising:bupivacaine or a salt thereof; phosphoric acid; a lipid componentcomprising at least one amphipathic lipid and at least one neutral lipidlacking a hydrophilic head group; and, optionally, a cholesterol and/ora plant sterol wherein said multivesicular liposomes are made by aprocess comprising: a) preparing a first aqueous component comprisingphosphoric acid; b) preparing a lipid component comprising at least oneorganic solvent, at least one amphipathic lipid, and at least oneneutral lipid lacking a hydrophilic head group; c) mixing said firstaqueous component and said lipid component to form a water-in-oilemulsion, wherein at least one component comprises bupivacaine or a saltthereof; d) mixing said water-in-oil emulsion with a second aqueouscomponent to form solvent spherules; and
 43. e) removing the organicsolvent from the solvent spherules to form multivesicular liposomesencapsulating bupivacaine phosphate. A method of inducing sensory blockin a subject, the method comprising injecting into the subarachnoidspace of the subject a pharmaceutical composition comprising: a) amultivesicular liposome comprising: at least one amphipathic lipid, andat least one neutral lipid; and b) an aqueous phase comprisingbupivacaine phosphate, wherein the aqueous phase is encapsulated withinthe multivesicular liposome.
 44. A method of inducing sensory block in asubject, the method comprising injecting into the subarachnoid space ofthe subject a pharmaceutical composition comprising multivesicularliposomes encapsulating bupivacaine phosphate, said multivesicularliposomes comprising: bupivacaine or a salt thereof; phosphoric acid; alipid component comprising at least one amphipathic lipid and at leastone neutral lipid lacking a hydrophilic head group; and, optionally, acholesterol and/or a plant sterol wherein said multivesicular liposomesare made by a process comprising: a) preparing a first aqueous componentcomprising phosphoric acid; b) preparing a lipid component comprising atleast one organic solvent, at least one amphipathic lipid, and at leastone neutral lipid lacking a hydrophilic head group; c) mixing said firstaqueous component and said lipid component to form a water-in-oilemulsion, wherein at least one component comprises bupivacaine or a saltthereof; d) mixing said water-in-oil emulsion with a second aqueouscomponent to form solvent spherules; and e) removing the organic solventfrom the solvent spherules to form multivesicular liposomesencapsulating bupivacaine phosphate.
 45. A method of anesthetizing asubject in need thereof, the method comprising injecting into thesubarachnoid space of the subject a pharmaceutical compositioncomprising: a) a multivesicular liposome comprising: at least oneamphipathic lipid, and at least one neutral lipid; and b) an aqueousphase comprising bupivacaine phosphate, wherein the aqueous phase isencapsulated within the multivesicular liposome.
 46. A method ofanesthetizing a subject in need thereof, the method comprising injectinginto the subarachnoid space of the subject a pharmaceutical compositioncomprising multivesicular liposomes encapsulating bupivacaine phosphate,said multivesicular liposomes comprising: bupivacaine or a salt thereof;phosphoric acid; a lipid component comprising at least one amphipathiclipid and at least one neutral lipid lacking a hydrophilic head group;and, optionally, a cholesterol and/or a plant sterol wherein saidmultivesicular liposomes are made by a process comprising: a) preparinga first aqueous component comprising phosphoric acid; b) preparing alipid component comprising at least one organic solvent, at least oneamphipathic lipid, and at least one neutral lipid lacking a hydrophilichead group; c) mixing said first aqueous component and said lipidcomponent to form a water-in-oil emulsion, wherein at least onecomponent comprises bupivacaine or a salt thereof; d) mixing saidwater-in-oil emulsion with a second aqueous component to form solventspherules; and e) removing the organic solvent from the solventspherules to form multivesicular liposomes encapsulating bupivacainephosphate.
 47. A method of reducing pain in a subject, the methodcomprising injecting into the subarachnoid space of the subject apharmaceutical composition comprising: a) a multivesicular liposomecomprising: at least one amphipathic lipid, and at least one neutrallipid; and b) an aqueous phase comprising bupivacaine phosphate, whereinthe aqueous phase is encapsulated within the multivesicular liposome.48. A method of reducing pain in a subject, the method comprisinginjecting into the subarachnoid space of the subject a pharmaceuticalcomposition comprising multivesicular liposomes encapsulatingbupivacaine phosphate, said multivesicular liposomes comprising:bupivacaine or a salt thereof; phosphoric acid; a lipid componentcomprising at least one amphipathic lipid and at least one neutral lipidlacking a hydrophilic head group; and, optionally, a cholesterol and/ora plant sterol wherein said multivesicular liposomes are made by aprocess comprising: a) preparing a first aqueous component comprisingphosphoric acid; b) preparing a lipid component comprising at least oneorganic solvent, at least one amphipathic lipid, and at least oneneutral lipid lacking a hydrophilic head group; c) mixing said firstaqueous component and said lipid component to form a water-in-oilemulsion, wherein at least one component comprises bupivacaine or a saltthereof; d) mixing said water-in-oil emulsion with a second aqueouscomponent to form solvent spherules; and e) removing the organic solventfrom the solvent spherules to form multivesicular liposomesencapsulating bupivacaine phosphate.
 49. A method of reducing an amountof opioid administered to a subject, the method comprising injectinginto the subarachnoid space of the subject a pharmaceutical compositioncomprising: a) a multivesicular liposome comprising: at least oneamphipathic lipid, and at least one neutral lipid; and b) an aqueousphase comprising bupivacaine phosphate, wherein the aqueous phase isencapsulated within the multivesicular liposome.
 50. A method ofreducing an amount of opioid administered to a subject, the methodcomprising injecting into the subarachnoid space of the subject apharmaceutical composition comprising multivesicular liposomesencapsulating bupivacaine phosphate, said multivesicular liposomescomprising: bupivacaine or a salt thereof; phosphoric acid; a lipidcomponent comprising at least one amphipathic lipid and at least oneneutral lipid lacking a hydrophilic head group; and, optionally, acholesterol and/or a plant sterol wherein said multivesicular liposomesare made by a process comprising: a) preparing a first aqueous componentcomprising phosphoric acid; b) preparing a lipid component comprising atleast one organic solvent, at least one amphipathic lipid, and at leastone neutral lipid lacking a hydrophilic head group; c) mixing said firstaqueous component and said lipid component to form a water-in-oilemulsion, wherein at least one component comprises bupivacaine or a saltthereof; d) mixing said water-in-oil emulsion with a second aqueouscomponent to form solvent spherules; and e) removing the organic solventfrom the solvent spherules to form multivesicular liposomesencapsulating bupivacaine phosphate.
 51. A method of reducing a durationof time during which an opioid is administered to a subject, the methodcomprising injecting into the subarachnoid space of the subject apharmaceutical composition comprising: a) a multivesicular liposomecomprising: at least one amphipathic lipid, and at least one neutrallipid; and b) an aqueous phase comprising bupivacaine phosphate, whereinthe aqueous phase is encapsulated within the multivesicular liposome.52. A method of reducing a duration of time during which an opioid isadministered to a subject, the method comprising injecting into thesubarachnoid space of the subject a pharmaceutical compositioncomprising multivesicular liposomes encapsulating bupivacaine phosphate,said multivesicular liposomes comprising: bupivacaine or a salt thereof;phosphoric acid; a lipid component comprising at least one amphipathiclipid and at least one neutral lipid lacking a hydrophilic head group;and, optionally, a cholesterol and/or a plant sterol wherein saidmultivesicular liposomes are made by a process comprising: a) preparinga first aqueous component comprising phosphoric acid; b) preparing alipid component comprising at least one organic solvent, at least oneamphipathic lipid, and at least one neutral lipid lacking a hydrophilichead group; c) mixing said first aqueous component and said lipidcomponent to form a water-in-oil emulsion, wherein at least onecomponent comprises bupivacaine or a salt thereof; d) mixing saidwater-in-oil emulsion with a second aqueous component to form solventspherules; and e) removing the organic solvent from the solventspherules to form multivesicular liposomes encapsulating bupivacainephosphate.
 53. The method of claim 49, 50, 51 or 52, wherein the opioidis administered to the subject following a surgical procedure in thesubject.
 54. The method of claim 53, wherein the opioid reduces pain inthe subject following the surgical procedure.
 55. A method of reducingan amount of a non-opioid analgesic administered to a subject, themethod comprising injecting into the subarachnoid space of the subject apharmaceutical composition comprising: a) a multivesicular liposomecomprising: at least one amphipathic lipid, and at least one neutrallipid; and b) an aqueous phase comprising bupivacaine phosphate, whereinthe aqueous phase is encapsulated within the multivesicular liposome.56. A method of reducing an amount of a non-opioid analgesicadministered to a subject, the method comprising injecting into thesubarachnoid space of the subject a pharmaceutical compositioncomprising multivesicular liposomes encapsulating bupivacaine phosphate,said multivesicular liposomes comprising: bupivacaine or a salt thereof;phosphoric acid; a lipid component comprising at least one amphipathiclipid and at least one neutral lipid lacking a hydrophilic head group;and, optionally, a cholesterol and/or a plant sterol wherein saidmultivesicular liposomes are made by a process comprising: a) preparinga first aqueous component comprising phosphoric acid; b) preparing alipid component comprising at least one organic solvent, at least oneamphipathic lipid, and at least one neutral lipid lacking a hydrophilichead group; c) mixing said first aqueous component and said lipidcomponent to form a water-in-oil emulsion, wherein at least onecomponent comprises bupivacaine or a salt thereof; d) mixing saidwater-in-oil emulsion with a second aqueous component to form solventspherules; and e) removing the organic solvent from the solventspherules to form multivesicular liposomes encapsulating bupivacainephosphate.
 57. A method of reducing a duration of time during which anon-opioid analgesic is administered to a subject, the method comprisinginjecting into the subarachnoid space of the subject a pharmaceuticalcomposition comprising: a) a multivesicular liposome comprising: atleast one amphipathic lipid, and at least one neutral lipid; and b) anaqueous phase comprising bupivacaine phosphate, wherein the aqueousphase is encapsulated within the multivesicular liposome.
 58. A methodof reducing a duration of time during which a non-opioid analgesic isadministered to a subject, the method comprising injecting into thesubarachnoid space of the subject a pharmaceutical compositioncomprising multivesicular liposomes encapsulating bupivacaine phosphate,said multivesicular liposomes comprising: bupivacaine or a salt thereof;phosphoric acid; a lipid component comprising at least one amphipathiclipid and at least one neutral lipid lacking a hydrophilic head group;and, optionally, a cholesterol and/or a plant sterol wherein saidmultivesicular liposomes are made by a process comprising: a) preparinga first aqueous component comprising phosphoric acid; b) preparing alipid component comprising at least one organic solvent, at least oneamphipathic lipid, and at least one neutral lipid lacking a hydrophilichead group; c) mixing said first aqueous component and said lipidcomponent to form a water-in-oil emulsion, wherein at least onecomponent comprises bupivacaine or a salt thereof; d) mixing saidwater-in-oil emulsion with a second aqueous component to form solventspherules; and e) removing the organic solvent from the solventspherules to form multivesicular liposomes encapsulating bupivacainephosphate.
 59. The method of claim 55, 56, 57 or 58, wherein thenon-opioid analgesic is administered to the subject following a surgicalprocedure in the subject.
 60. The method of claim 59, wherein the opioidreduces pain in the subject following the surgical procedure.
 61. Themethod of any one of claims 41 to 60, wherein the pain is in a regionbelow the diaphragm.
 62. The method of claim 61, wherein the pain isselected from abdomen pain, lower back pain, hip pain, pelvic pain,femur pain, knee pain, knee pain, foot pain, and ankle pain.
 63. Themethod of any one of the preceding claims, wherein the subject does notexperience neurological side effects.
 64. The method of any one of thepreceding claims, wherein the subject does not experience cardiac sideeffects.